Showing posts with label a. Show all posts
Showing posts with label a. Show all posts
Thursday, November 20, 2014
A 4 Digit Keypad Controller Switch Circuit
This is a universal version of the Four-Digit Alarm Keypad . I have modified the design to free up the relay contacts. This allows the circuit to operate as a general-purpose switch. It also means that it can be used to control all of my Alarm Circuits. Ive used a SPCO/SPDT relay - but you can use a multi-pole relay if you wish.
The relay is energized by pressing a single key. Choose the key you want to use - and connect it to terminal "E". Choose the four keys you want to use to de-energize the relay - and connect them to "A B C & D". Wire the common to R1 and all the remaining keys to "F".
The Circuit is easy to use. When you press "E" - current through D2 & R9 turns Q6 on - and energizes the relay. The two transistors - Q5 & Q6 - form a "Complementary Latch". So - when you release the key - the relay will remain energized.
To de-energize the relay - you need to press keys "A B C & D" in the right order. When you do so - pin 10 of the IC goes high - and it turns Q4 on through R8. Q4 connects the base of Q6 to ground. This unlatches the complementary pair - and the relay drops out.
Any keys not wired to "A B C D & E" are connected to the base of Q3 by R7. Whenever one of these "Wrong" keys is pressed - Q3 takes pin 1 low and the code entry sequence fails. If "C" or "D" is pressed out of sequence - Q1 or Q2 will also take pin 1 low - with the same result. If you make a mistake while entering the code - simply start again.
The Keypad must be the kind with a common terminal and a separate connection for each key. On a 12-key pad, look for 13 terminals. The matrix type with 7 or 8 terminals will NOT do. With a 12-key pad - over 10 000 different codes are available. If you need a more secure code - use a bigger keypad with more "Wrong" keys wired to "F". A 16-key pad gives over 40 000 different codes.
The relay is energized by pressing a single key. Choose the key you want to use - and connect it to terminal "E". Choose the four keys you want to use to de-energize the relay - and connect them to "A B C & D". Wire the common to R1 and all the remaining keys to "F".
The Circuit is easy to use. When you press "E" - current through D2 & R9 turns Q6 on - and energizes the relay. The two transistors - Q5 & Q6 - form a "Complementary Latch". So - when you release the key - the relay will remain energized.
To de-energize the relay - you need to press keys "A B C & D" in the right order. When you do so - pin 10 of the IC goes high - and it turns Q4 on through R8. Q4 connects the base of Q6 to ground. This unlatches the complementary pair - and the relay drops out.
Any keys not wired to "A B C D & E" are connected to the base of Q3 by R7. Whenever one of these "Wrong" keys is pressed - Q3 takes pin 1 low and the code entry sequence fails. If "C" or "D" is pressed out of sequence - Q1 or Q2 will also take pin 1 low - with the same result. If you make a mistake while entering the code - simply start again.
The Keypad must be the kind with a common terminal and a separate connection for each key. On a 12-key pad, look for 13 terminals. The matrix type with 7 or 8 terminals will NOT do. With a 12-key pad - over 10 000 different codes are available. If you need a more secure code - use a bigger keypad with more "Wrong" keys wired to "F". A 16-key pad gives over 40 000 different codes.
Thursday, November 13, 2014
13 8V 20A DC Power Supply
The following DC Power supply circuit is a linear power supply (using transformer). The voltage output of 13.8V power supply is highly regulated, can be adjusted in the moderate range, at up to 20A continuous current. This power supply is suitable for use for amateur radio equipment. DC Power supply is easily constructed and suitable for heavy duty because it is very efficient, small and lightweight.
In the DC power supply presented here, the pass transistors are located in the negative rail and connected in common-emitter configuration rather than as emitter-followers. Thanks to this, the regulator’s minimum voltage drop is extremely low, only about 0.1V for the transistors plus 0.5V for the equalizing resistors.
DC Power Supply Circuit
The other advantage is that the collectors are directly connected to the negative pole of the power supply’s output, which in most applications is grounded. That means that no insulation is required between the transistors and the grounded power supply cabinet! This eases the cooling very considerably. Thanks to the low regulator drop, a low cost 25V filter capacitor can be used.
Some Notes of DC Power Supply Circuit
- Use a transformer for the primary voltage you need. The 3A fuse is for 220 or 240V primaries. If you use something in the neighborhood of 110V, use a 6A fuse.
- The rather high transformer rating of 35A accounts for the losses that occur due to the capacitive input filter. If your transformer is rated for capacitive input, then a 25A value is enough.
- Of course you can make up C1 by placing several smaller capacitors in parallel. Likewise, the 0.1 Ohm, 5 Watt resistors can be made up by several in parallel, for example by 5 resistors of 0.5 Ohm, 1 Watt each.
- The LM336Z-5.0 voltage reference IC should not be replaced by a zener diode. Zeners are not nearly as stable. A different voltage reference IC can of course be used, if R2 and R3 are modified for the different voltage.
- D1 and Q2 through Q6 need heatsinking. Only Q2 needs insulation. D1 dissipates up to 60W, Q2 up to 25W, while the pass transistors dissipate up to 30W each in normal use, but may reach a level of 130W during short circuit! Take this into account when choosing the heat sink!
- R5 exists only to make sure that the transistors can actually be driven off. The 741 is not a single-supply operational amplifier, so it cannot drive its output very low. If a true single-supply opamp is used, then R5 becomes unnecessary.
Wednesday, November 12, 2014
Build a 500W Low Cost 12V to 220V Inverter
Attention: This Circuit is using high voltage that is lethal. Please take appropriate precautions
Using this circuit you can convert the 12V dc in to the 220V Ac. In this circuit 4047 is use to generate the square wave of 50hz and amplify the current and then amplify the voltage by using the step transformer.
How to calculate transformer rating
The basic formula is P=VI and between input output of the transformer we have Power input = Power output
Using this circuit you can convert the 12V dc in to the 220V Ac. In this circuit 4047 is use to generate the square wave of 50hz and amplify the current and then amplify the voltage by using the step transformer.
How to calculate transformer rating
The basic formula is P=VI and between input output of the transformer we have Power input = Power output
For example if we want a 220W output at 220V then we need 1A at the output. Then at the input we must have at least 18.3V at 12V because: 12V*18.3 = 220v*1
So you have to wind the step up transformer 12v to 220v but input winding must be capable to bear 20A.
Wednesday, November 5, 2014
How To Make a Two Line Intercom Cum Telephone Line Changeover
The circuit presented here can be used for connecting two telephones in parallel and also as a 2-line intercom. Usually a single telephone is connected to a telephone line. If another telephone is required at some distance, a parallel line is taken for connecting the other telephone. In this simple parallel line operation, the main problem is loss of privacy besides interference from the other phone. This problem is obviated in the circuit presented here. Under normal condition, two telephones (telephone 1 and 2) can be used as intercom while telephone 3 is connected to the lines from exchange. In changeover mode, exchange line is disconnected from telephone 3 and gets connected to telephone 2.
2-Line Intercom-Cum-Telephone Line Changeover Circuit Diagram
For operation in intercom mode, one has to just lift the handset of phone 1 and then press switch S1. As a result, buzzer PZ2 sounds. Simultaneously, the side tone is heard in the speaker of handset of phone 1. The person at phone 2 could then lift the handset and start conversation. Similar procedure is to be followed for initiation of the conversation from phone 2 using switch S2. In this mode of operation, a 3-pole, 2-way slide-switch S3 is to be used as shown in the figure. In the changeover mode of operation, switch S3 is used to changeover the telephone line for use by telephone 2. The switch is normally in the intercom mode and telephone 3 is connected to the exchange line.
Before changing over the exchange line to telephone 2, the person at telephone 1 may inform the person at telephone 2 (in the intercom mode) that he is going to changeover the line for use by him (the person at telephone 2). As soon as changeover switch S3 is flipped to the other position, 12V supply is cut off and telephones 1 and 3 do not get any voltage or ring via the ring-tone-sensing unit. Once switch S3 is flipped over for use of exchange line by the person at telephone 2, and the same (switch S3) is not flipped back to normal position after a telephone call is over, the next telephone call via exchange lines will go to telephone 2 only and the ringtone-sensing circuit will still work. This enables the person at phone 3 to know that a call has gone through. If the handset of telephone 3 is lifted, it is found to be dead. To make telephone 3 again active, switch S3 should be changed over to its normal position.
Tuesday, November 4, 2014
Build a Peak Indicator
How to build a peak indicator circuit . Each time where the level of signal exceeds the level + 4dB, turns on led D1. It is useful in each channel of console of sound, in final amplifiers or in that other application, to we needed. With the prices of circuit, the indicate begins with levels above + 4 dB (1.25V rms). For adaptation in different levels of signal, we can use a trimmer, before capacitor C1.
Peak Indicator Circuit Diagram :
R1 = 10K
R2 = 1.2K
R3 = 220K
R4 = 4.7K
R5 = 4.7K
C1 = 47uF-25V
C2 = 2.2uF-25V
Q1 = BC550C
Q2 = BC550C
D1 = Red LED
Notes:
- It can be assembled on a general purpose PCB.
- It can be powered from a 12V-15V regulated power supply.
Monday, November 3, 2014
A Car Battery Monitor
A close call on the road can really focus your mind on the importance of having a battery monitor in a car. I had been enjoying a pleasant week of travelling around the countryside at a leisurely pace and taking in the beautiful scenery each day. It wasnt until the final day, with the big rush to return home, that I had to drive at night.My home is deep in the country and on the road I was travelling the closest petrol station may be 80km away. I was travelling through an area that is full of open-cut coal mines and large heavily loaded semi-trailers constantly pound the roads, travelling at quite high speeds. It was around 8pm at night and everything was very dark no street lights or house lights anywhere.
Just as I was going up a hill, the lights began to dim and the engine coughed. A large semi-trailer loomed in the rear-vision mirror as I pushed the clutch in and tried to restart. My speed was falling rapidly and my lights were blacked out - I was like a sitting duck in the middle of the road, as the semi-trailer came rapidly bearing down on me.
I just managed to pull the car off the road, as the semi-trailer came screaming past, missing me by inches! After calling for assistance from the NRMA, the problem was found to be a fault in the alternator, which was failing to charge the battery. The battery voltage had been falling under the heavy load of the lights and at the worst possible time, there was not sufficient power for the lights or the motor.
After the initial shock wore off, I put on my thinking cap to come up with a PIC-based solution to the problem. What was really needed was a display and a buzzer, to get my attention should the voltage fall outside a specified range. So my design criteria was set, a series of LEDs could indicate the voltage and a buzzer would also be used to warn of problems.
Main Features:
- Visual indication of battery voltage
- Audible warning when voltage becomes low
- Screw terminals for easy connection
- Simple and easy to build
Circuit details:
The circuit is based on PIC16F819 18-pin microcontroller which has an analog-to-digital (A/D) input to monitor the battery voltage and outputs capable of driving LEDs directly, to keep the component count down. There are seven LEDs in all, giving a good range of voltage indication. The topmost LED, LED1, comes on for voltages above 14V which will occur when the battery is fully charged. LED2 indicates for voltages between 13.5V and 14V while LED3 indicates between 13V and 13.5V.
Normally, one of these LEDs will be on. LED4 covers 12.5V to 13V while LED5 covers 12V to 12.5V. LED6 covers from 11.5V to 12V while LED7 comes on for voltages below 11.5V. These two LEDs are backed up by the piezo chime which beeps for voltages between 11.5V and 12V and becomes more insistent for voltages below 11.5V.
That might seem fairly conservative. After all, most cars will start with no troubles, even though the battery voltage might be a touch below 12V, wont they? Well, no. Some modern cars will happily crank the motor at voltages below 11V but their engine management will not let the motor start unless the voltage is above 11V.
So dont think that a modern car will always start reliably. This little battery monitor could easily prevent a very inconvenient failure to start! So lets describe the rest of the circuit. The incoming supply is connected via diode D1 which provides protection against reverse polarity while zener diode ZD1 provides protection from spike voltages.
A standard 7805 3-terminal regulator is then used to provide a stable 5V to the microcontroller. The battery voltage is sensed via a voltage divider using 33kΩ and 100kΩ resistors. This brings the voltage down to within the 0-5V range for the A/D input of the PIC16F819. Port B (RB0 to RB7) of the microcontroller is then used to drive the various LEDs, with current limiting provided via the 330Ω resistor network. RB7, pin 13, drives a switching transistor for the piezo buzzer.
Software:
For the software, the design follows the basic template for a PIC microcontroller. Port A and its ADC (analog-to-digital converter) function are set up while port B functions as the output for the LEDs and buzzer. Once the set-up is complete, a reading will be taken at port RA2, the input for the A/D convertor. This reading is then compared with a series of values to determine the range of the voltage. This is similar to a series of "if" statements in Basic language.
If the voltage is found to be within a certain range, the relevant port B pin will be turned on. If the voltage is below 12V, the buzzer will be turned on for a brief period, to signal a low battery condition. As the voltage falls below 11.5V, the frequency of the beeps will increase, to signal increased urgency.
Building it:
All the parts are mounted on a small PC board measuring 46 x 46mm (available from Futurlec). The starting point should be the IC socket for the PIC16F819, as this is easiest to mount while the board is bare. The next item can be the PC terminal block. The resistors and capacitors can then follow. Make sure the electrolytics are inserted with correct polarity.
Make sure that you do not confuse the zener (ZD1) with the diode when you are installing them; the diode is the larger package of the two.
Even more important, dont get the 78L05 3-terminal regulator and the 2N3906 transistor mixed up; they come in identical packages. The 78L05 will be labelled as such while the 2N3906 will be labelled "3906". And make sure you insert them the correct way around. The buzzer must also be installed with the correct polarity. The 330Ω current limiting resistors are all in a 10-pin in-line package. There are four green LEDs, two yellow and one red. They need to be installed in line and with the correct orientation.
Testing:
Before you insert the PIC16F819 microcontroller, do a voltage check. Connect a 12V source and check for the presence of 5V between pins 14 & 5 OF IC1. If 5V is not present, check the polarity of regulator REG1 and the polarity of the diode D1. If these tests are OK, insert the IC and test the unit over a range of voltage between 9V and 15V. Make sure that all LEDs come on in sequence and the piezo buzzer beeps for voltages below 12V.
Now it is matter of installing the unit in your car. It is preferable to install the unit in a visible position for the driver. However, it should not obscure any other instruments. The unit should be connected to the cars 12V supply after the ignition switch. This will turn the unit off with the other instruments and prevent battery drain while the motor is not running.
Wednesday, October 29, 2014
A mini roulette system
A mini roulette circuit, as soon as the switch S1 the output next to pin 1 of the IC1a the voltage is “sharp”,The oscillator circuit output IC2b, IC2c work out.alarm clock pulse generator fed to IC3, a voltage “high” output to the output pins 3, 11, and pin 12 of the IC3, the LED1-LED10 light track sequence. Section LED11 parade high - low instant. The output of pin 3, 2, 4, 7, 10, of IC3 represented by high points,Output pins 1, 5, 6, 9, 11 as a replacement for of the IC3 with the low points.The roll-over prize meant for the LED12.The IC1b, IC2a and IC2d like controls.
Resistor R2 and capacitor C1 determine the punctuation mark of the output “excessive” output from pin 1 of the IC1a. The capacitor C1 through R2. as you press the switch and the voltage shelve across C1 spirit little by little swell until the greatest level. It will reset the flip fall down IC1a suit the output next to pin 1 is “low”. And the oscillator output circuit to pause working, but at hand are a number of LED illumination are pending, it might exist to facilitate we close up being the LED. So carry out not concern, it desire switch a only some time.since, particular a schedule punctuation mark with the aim of the R2 and C1. The diplomacy are compulsory to keep a 6-volt power supply. If distorted is 9 volts, requisite try representing security reasons.
Thursday, October 23, 2014
Schematic diagram of a USB player
Usb series player is an electronic device or electronic circuit that functions as an MP3 player that is stored on a storage device such as USB flash.In this usb circuit using an IC as a modifier of digital voice data into analog so that it can be applied to a headphone, or again through the power amlplifier strengthened so that it can be heard through the speakers. IC used in this circuit using IC PCM2902 as a modifier of a digital data into analog data storage.
Below is a schematic diagram of a USB player.
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| Schematic usb player |
Running Light circuit uses a CMOS 555 timer
A Transcutaneous Electrical Nerve Stimulation (TENS) device is, put bluntly, a machine for giving electric shocks. The author was prescribed such a device on loan by his orthopaedic specialist. The unit has a large number of programmes, of which he used only one. Measuring the signals at the output of the device in this mode revealed damped oscillations at a frequency of approximately 2.5 kHz, with a repetition rate of approximately 100 Hz.
Read More..
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| Running Light circuit uses a CMOS 555 timer |
How hard can it be to make such a device ourselves? The simple circuit uses a CMOS 555 timer to produce a brief pulse which feeds a 1:10 miniature transformer. Together with a 4.7 nF capacitor the transformer makes a parallel resonant circuit: the resonance leads to a considerable increase in the output voltage. The pulse width can be adjusted using a potentiometer, here shown combined with the on-off switch. Wider pulses produce higher output voltages. Since a peak voltage of up to 200 V can be produced, the transformer must have adequate insulation: Conrad Electronics type 516260-62 is suitable. A low-cost phono socket at the output gives reliable connection to the electrode cable.
The adhesive electrodes shown in the photograph (disposable and permanent types are available) can be obtained from pharmacies and medical suppliers. They generally have connectors compatible with 2 mm banana plugs, and so it is possible to make up the necessary cable yourself. To treat responsive parts of the body, such as the arm, the potentiometer need not be turned up far to obtain the necessary sensation. Less sensitive parts, such as the knee or foot, need a rather higher voltage and hence a correspondingly higher potentiometer setting.
Author: Klaus Rohwer – Copyright: Elektor Electronics Magazine
Link:http://www.extremecircuits.net/2010/06/transcutaneous-electrical-nerve_03.html
Friday, October 17, 2014
Build a Ultrasonic Dog Whistle
Its well known that many animals are particularly sensitive to high-frequency sounds that humans cant hear. Many commercial pest repellers based on this principle are available, most of them operating in the range of 30 to 50 kHz. My aim was, however, to design a slightly different and somewhat more powerful audio frequency/ultrasonic sound generator that could be used to train dogs. Just imagine the possibilities - you could make your pet think twice before barking again in the middle of the night or even subdue hostile dogs (and I guess burglars would love that!).
From what Ive read, dogs and other mammals of similar size behave much differently than insects. They tend to respond best to frequencies between 15 and 25 kHz and the older ones are less susceptible to higher tones. This means that an ordinary pest repeller wont work simply because dogs cant hear it. Therefore, I decided to construct a new circuit (based on the venerable 555, of course) with a variable pitch and a relatively loud 82 dB miniature piezo beeper.
The circuit is very simple and can be easily assembled in half an hour. Most of the components are not really critical, but you should keep in mind that other values will probably change the operating frequency. Potentiometer determines the pitch: higher resistance means lower frequency. Since different dogs react to different frequencies, youll probably have to experiment a bit to get the most out of this tiny circuit. The circuit is shown below:
Ultrasonic Dog Whistle Circuit diagram
From what Ive read, dogs and other mammals of similar size behave much differently than insects. They tend to respond best to frequencies between 15 and 25 kHz and the older ones are less susceptible to higher tones. This means that an ordinary pest repeller wont work simply because dogs cant hear it. Therefore, I decided to construct a new circuit (based on the venerable 555, of course) with a variable pitch and a relatively loud 82 dB miniature piezo beeper.
The circuit is very simple and can be easily assembled in half an hour. Most of the components are not really critical, but you should keep in mind that other values will probably change the operating frequency. Potentiometer determines the pitch: higher resistance means lower frequency. Since different dogs react to different frequencies, youll probably have to experiment a bit to get the most out of this tiny circuit. The circuit is shown below:
Ultrasonic Dog Whistle Circuit diagram
Despite the simplicity of the circuit, there is one little thing. The 10nF (.01) capacitor is critical as it, too, determines the frequency. Most ceramic caps are highly unstable and 20% tolerance is not unusual at all. Higher capacitance means lower frequency and vice-versa. For proper alignment and adjustment, an oscilloscope would be necessary. Since I dont have one, I used Winscope. Although its limited to only 22 kHz, thats just enough to see how this circuit works.
There is no need to etch a PCB for this project, perf board will do. Test the circuit to see how it responds at different frequencies. A 4k7 potentiometer in conjunction with a 10nF (or slightly bigger) capacitor gives some 11 to 22kHz, which should do just fine. Install the circuit in a small plastic box and if you want to, you can add a LED pilot light. Power consumption is very small and a 9V battery should last a long time. Possible further experimentation:
Im working on an amplified version of the whistle to get a louder beep. All attempts so far havent been successful as high frequency performance tends to drop dramatically with the 555. Perhaps I could use a frequency doubler circuit - I just dont know and Ive run out of ideas. One other slightly more advanced project could be a simple "anti-bark" device with a sound-triggered (clap) switch that sets off the ultrasonic buzzer as soon as your dog starts to bark.
Wednesday, October 15, 2014
Build a 10 LED Bar Dot VU Meter Circuit based LM3915
Build a 10 LED Bar Dot VU meter circuit based LM3915. It differs in many respects from other applications on the same chip. The circuit is intended for those who want a VU meter that is connected directly to the output of an power amplifier.
10 LED Bar Dot VU Meter Circuit based LM3915 Circuit Diagram
It’s possible to adjust the sensitivity to work with amplifiers that have different output power, you just need to change the value of R1 according to Table 1. In case you did’n find the exact resistor value, then choose the next standard value (for example if you cannot find 33K ohm, then find the 36K ohm), or if you want maximum accuracy you need to put resistors in series or in parallel to achieve the correct value.
You can use various types of LEDs (round or square) to get the visual and aesthetic result you want. The switch S1 will allow you to choose whether VU meter will work as a bar or one by one (dot). In position ON [closed switch], the LED operation is Bar, while in position OFF [open switch], the LED operate in Dot. In Bar mode, the power consumption rises because all of the LED will be work and can reach up to 150mA.
For amplifier with two channels is obvious that we should build two identical circuits, one for each channel. The operating voltage of the circuit is +12 V. Taking this trend should be done by the tendency of the amp. Usually amps work with voltages which higher than +12 Volts for the circuit. For this reason, we must added a component which can decrease, regulate and stabilize the +Vp voltage at +12 Volts. The component we are used is IC2 (LM317) which is an adjustable voltage regulator and stabilizer.
Using a small brushing is necessary because the differences in the potential entry; output is large so that we develop high levels of temperature. The use of R5 helps in voltage drop to descend the voltage at the input of IC2 at lower levels. The calculation of this resistance is more empirically using Ohm’s law. The voltage at the input of IC2 must be higher than +16 Volts. For example, if the voltage of the amplifier is +50 Volts, we should have a voltage drop 50-16 = 34 Volts on the resistance R5. For the electric current, 50mA average is needed by the circuit [may be up to 150mA], the value of R5 = V / I = 34/0.05 = 680 ohms 2W. You may need to increase or decrease this value by trials. Because the resistor is going to heat up, then it will be better to put some distance from the PCB.
It will be better to set up and measure the output vltage of the IC2 by adjusting TR1 first, you need yo remove IC1 to secure the IC1. If you are able to supply the stabilized +12 V from somewhere in the amplifier circuit, then you’ll need to remove the R5, the IC2 and materials inside the dotted line.
PCB layout design:
Friday, September 19, 2014
Build a Automatic Water Tank Filler Wiring diagram Schematic
This schema has been very useful in filling a header tank for a reticulated water supply on a farm. Eight troughs are supplied in different paddocks where a lack of water would have serious consequences for the stock. In the past, the tank had been filled daily by a time clock which was not successful. During hot weather, the stock would empty the tank on a regular basis and then be without water for several hours or the tank would overflow and flood the area if the weather was wet and the cattle did not drink much.1
Automatic Water Tank Filler Circuit Diagram
Automatic Water Tank Filler Schematic Circuit Diagram
The schema described has been used to maintain the level of water in the header tank within prescribed limits. It controls a 3HP submersible bore pump which has a high starting current, necessitating a solid-state relay sufficient to take the starting load. Two Darlington transistors, Q1 & Q3, in conjunction with Q2 & Q4, are connected to the upper and lower water sensors in the tank. Q2 & Q4 have a common 5.6kO load resistor and function as a NOR gate. The output of the NOR gate drives Q5 which activates relay RLY1.
Initially, when the water level is low, both sensors will be open-schema, the NOR gate output will be high and the relay will be turned on. This causes the normally closed (NC) contacts of the relay to open and disconnect the lower sensor. However, the upper sensor will still be open schema and the NOR gate output will be high, keeping the relay closed. The normally open (NO) contact of the relay will be closed to operate the solid-state relay RLY2 to run the pump.
This state continues until the water reaches the top sensor which will then drop the output from the NOR gate to 0V. The disables relay RLY1 and the pump is stopped. In practice the upper level sensor is just below the overflow from the tank and the lower sensor about half way up the tank. The sensor contacts are simply two stainless steel screws about 25mm apart and screwed through the poly tank walls. The wiring junctions on the side of the tank are protected by neutral-cure silicone sealant.
Sunday, September 14, 2014
Long Duration Timer using A Ttiny 2313
This timer schema is designed to switch on a 12 V load in a solar-powered installation for a preset period at the press of a button. When the period has expired a latching relay disconnects both the load and the controller schema from the 12 V supply. The length of the period can be configured by making suitable changes to the microcontroller’s source code.
When button S1 is pressed a voltage appears across relay coil L1, and the relay switches the load on. Since the relay is a latching type, it remains in this state when the but ton is released. There is now a supply to the 78L05 voltage regulator (a low-dropout type such as the LP2950CZ-5.0 may also be used) and the microcontroller is powered up. In the microcontroller the timer program runs until the configured time interval has elapsed. Around 90 % of the way through the time period LED D2 lights as a warning that the load will shortly be switched off, and this time can also of course be configured by changing the software.
When the full time interval has elapsed the microcontroller sets an output (pin 7) high, which triggers the CNY 17-3 optocoupler and in turn drives relay coil L2. The relay returns to its initial state, disconnecting the load as well as the controller (which is also powered via the relay contact) from the 12 V supply.
Long Duration Timer Circuit Diagram
The author used a miniature 16 -by-2 LCD panel type HMC16223SG in his prototype, measuring just 52 mm by 20 mm. It is of course possible to use any standard LCD module that uses an HD44780-compatible controller. Note that P1 is used to adjust the contrast of the LCD: if the display appears blank it is worth checking the contrast set-ting before suspecting a more serious problem! If desired, the LCD can be dispensed with, along with the corresponding parts of the source code.
The upper line of the LCD shows the total time period, in seconds, for which the soft-ware is configured, while the lower line shows the time, in seconds, since the button was pressed.
The Lcddump shows the LCD settings under BASCOM-AVR. The source code for the program is available for download. Link
Monday, September 8, 2014
Build a Current Booster Wiring diagram Schematic
This is a simple Current Booster Circuit Diagram. The LT1012 corrects de errors in the booster stage, and does not set high-frequency signals. Fast signals are fed directly to the stage via Q5 and the 0.01-uF coupling capacitors. De and low-frequency signals drive the stage via the op-amp`s output.
The output stage consists of current sources, Q1 and Q2, driving the Q3-Q5 and Q4-Q7 complementary emitter follows. The diode network at the output steers drive away from the transistor bases when output current exceeds 250 mA, providing fast short-schema protection.
Current Booster Circuit Diagram
The schema`s high frequency summing node is the junction of the 1-K and 10-K resistors at the LT1012. The 10 K/39 pF pair filters high frequencies, perruitting accurate de summation at the LT1012`s positive input. This current-boosted amplifier has a slew rate in excess of 1000 Vii`s, a full power bandwidth of 7.5 MHz and a 3-dB point of 14 MHz.
Thursday, September 4, 2014
Build a Agc System For Ca3028 Rf Amplifier Wiring diagram Schematic
Build a Agc System For Ca3028 Rf Amplifier Circuit Diagram. An MPF102 amplifier feeds IF signals to a 2N4126. A potentiometer in the MPF102 source acts as a gain control. This voltage is rectified by an 1N914 doubling detector, and drives a 741 op amp via a source follower (Q14). S-meter and IF-gain controls are provided.
Agc System For Ca3028 Rf Amplifier Circuit Diagram
Sunday, August 31, 2014
Power Amplifier Class A circuit
This is a design schematic Class A power amplifier . This is a close as possible in operating parameter the Under Classes is class B , to aid comparison ; in particular the NFB factor remains 30dB at 20 kHz. The front end is similiar to class B amplifier. This circuit uses a standart quasi output. This may be replaced by a CFP stage without problems. In both cases the distortion is extremely low, but gratifyingly the CFP proves even better than quasi , confirming the simulation results for output stages in isolation.
About Class-A amplifier , in this class is the highest class from another class. Classes below begin from AB to Class S. In a Class-A amplifi er current fl ows continuously in all the output devices, which enables the nonlinearities of turning them on and off to be avoided. They come in two rather different kinds, although this is rarely explicitly stated, which work in very different ways. The fi rst kind is simply a Class-B stage (i.e. two emitter-followers working back to back) with the bias voltage increased so that suffi cient current fl ows for neither device to cut off under normal loading.
The great advantage of this approach is that it cannot abruptly run out of output current; if the load impedance becomes lower than specifi ed then the amplifi er simply takes brief excursions into Class-AB, hopefully with a modest increase in distortion and no seriously audible distress.
This is schematic power amplifier class A below :
About Class-A amplifier , in this class is the highest class from another class. Classes below begin from AB to Class S. In a Class-A amplifi er current fl ows continuously in all the output devices, which enables the nonlinearities of turning them on and off to be avoided. They come in two rather different kinds, although this is rarely explicitly stated, which work in very different ways. The fi rst kind is simply a Class-B stage (i.e. two emitter-followers working back to back) with the bias voltage increased so that suffi cient current fl ows for neither device to cut off under normal loading.
The great advantage of this approach is that it cannot abruptly run out of output current; if the load impedance becomes lower than specifi ed then the amplifi er simply takes brief excursions into Class-AB, hopefully with a modest increase in distortion and no seriously audible distress.
This is schematic power amplifier class A below :
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| Click image to view larger |
The operation of current regulator TR13 , TR15 , TR 16 has already been described. The reference used is a National LM385/1.2 Its output voltage is fixed at 1.233 V nominal ; this is reduced approximately 0.6V by 1k - 1k divider . The circuit is the best for me , because is loudly , and does not vibrate the speakers leaves , softly sound , and low noise . And i like it .,., :)
For the hobby electronics especially in the amplifier , is suitable to be tried.
Tuesday, August 26, 2014
A advantage sports car Sound classification is a Requirement not a Luxury
How accomplish you decide which sedan sound system is most excellent on behalf of you? This is a question to facilitate many consumers ask wearing the U. S. every and all sunlight hours. The reality is that just you can decide come again? kind of sound you catch enjoyable and what you are seeking in the sound structure you pray ultimately hold. A good sound system will greatly look up how you feel just about not merely the vehicle you drive but moreover your disposition afterward your on a daily basis exchange. It might seem like such a slight mechanism, the changing of a sound classification, but it does seem to contain such a profound collision on how we start our days. Of classes we all know with the aim of getting your generation sour to a benefit start sets the tone in favor of the whole day and if that day is Monday it sets the tone for not just the generation yet to be but plus the week to happen.
Tune affects almost all aspect of our lives. the majority of us resolve not realize the crash with the intention of melody has on our time-to-day lives and it is quite hard as our humanity seems to remain overflowing with it. It is much easier however, to explain the difference a good sound arrangement makes. Its funny, I discover myself taking part in a hurry through to step unacceptable of supplies so as to take lousy sound systems and speakers that seep out small other than static while I can store pro hours in a stock with the intention of has refined melody singing in the background above a high-quality sound approach. I favor the volume drop and the melody in concert in the background pretty than being the concentrate of my attention.
Generally of us acquire so as to soft song singing at home the background is rather low profile and allows us to become along with our belief and the mission by give while loud tune piercing larger than very old speakers does a lofty deal to disrupt our notions processes which want simply achieve to send off us along to the subsequently chore on our make a list. If youll notice it seems to facilitate clerks inside the provisions everyplace the loud harmony blares along are often not such as even tempered as individuals in food to recreation song by the side of polite volumes and obtain very well set aside sound systems. I think I would remain ratty too subsequent to listening to melody in a way to music wasnt destined to be heard.
Im not a harmony snob by in the least revenue; I simply benefit from listening to melody designed for the sake of in point of fact investigation the tune. Loud music is fine every so often but not once I have other things on my mind. I have a preference with the purpose of song keep on featuring in the background as soon as Im running on the subject of taking worry of errands, even in the car. The token of a good sedan sound logic is to it sounds good even on low volumes. This agency you can have song in the background, hum along, or else simply ignore the song in approve of the clash taking place on the road.
The intention Im tiresome to produce is to even though you could not realize the influence that a good sports car sound scheme has on harmony right now, you desire undeniably feel the difference it makes above occasion. The better the sound system, the better the sound and harmony is taking into account all, sound.
If you are a devoted lover of melody and squander a celebrated deal of your week otherwise even every certain daylight hours concerning your vehicle, doesnt it make meaning to invest closely in your car sound practice? I know in favor of me with the aim of fussy decision is a nix brainer. I fondness harmony and it is an valuable part of not barely my life but as well the lives of my children. for instance a conclusion we splurge a allotment of clock listening to the data lines arrived our SUV and singing along. Even once we arent listening to melody, I have listening colloquy broadcasting and the news on NPR. These things are an essential part of my era and I really have all to both and all single adds to my life. since of that, I achieve my investment in a useful sedan sound classification to come to pass a requirement relatively than a luxury.
Building a radio station
Requires us to make things systematically and efficiently, because time is very valuable to us, then some of the advances in technology has been applied in various fields, including education, because this is where all the technological advances developed.Lots of technology is rapidly expanding in our country today. With technology growing by leaps and bounds this is what will make the work more systematic and efficient.Based on our technological advances and his friends create a system are related to the Electronics course, we propose the same faculty to develop a community tool. We got a second job in four semesters, which makes the FM transmitter.
Departing from hobby assembling electronic items, we try to assemble a mini-power transmitter that can emit a short signal of approximately 100 meters with power (power) 5 watts. This is a pilot who later became 12 watts. With 12 watts of power, radio broadcasts to reach a village.
1.2 Formulation of ProblemProblems are handled from this lab assignment is to create and analyze the quality of an FM transmitter to get the data at test point 1, point 2 test, test point 3 and the exact frequency as desired.Things are of practical tasks is restricted only to analyze the quality of a transmitter and retrieve data from an existing test point.
1.3 LimitationsProblems to be addressed in this lab assignment is limited to some of the following:1 • Retrieving data from the frequency and calculate TP 1 to TP 3.2 • Analyze a transmitter in the room, based on measurement data and make conclusions.
1.4 ObjectivesObjectives to be achieved in this task are:A. Students can design and make the circuit in fm transmitter.2. 12 Watt FM transmitter that can be made of appropriate tools and can be marketed.
1.5 MethodologyIn completing this lab assignment, the steps are as follows:1 • Learn about basic electronics concepts and learn concepts about the mechanism of FM modulation.2 • Analyze and conclude the experimental results, and give advice when it is applied to the practical task of the real system.3 • Preparing a report on second semester practicum assignment.
1.6 DiscussionThis book of this lab assignment consists of 5 (five) chapters, in each chapter related to one another, namely:
CHAPTER 1:Provide background on the issues, goals, problems and constraints of the problems discussed in this lab assignment.CHAPTER 2:Provide the theoretical basis to support problem solving in this lab assignment. The basic theory is given include: the mechanism of the tool inused in making the FM transmitter
CHAPTER 3:Planning and manufacture of tools and how each blog diagram contained in FM transmitterCHAPTER 4:Contains the results of calculations and data processing, and analysis resultscalculation.CHAPTER 5:Provide conclusions about the results already obtained and suggestions.CHAPTER IIBASIC THEORY
2.1 Koker
Koker serves to regulate or determine the frequency of the radio transmitter. In koker also Ferrite that serves as a core inductor in addition there is an inductance coil comprising primary and secondary winding. Way of working is to facilitate search koker empty wave. When filling koker in turn to the right to a maximum frequency of the oscillator produce more low. If the FM transmitter lights, turn left up the core koker to hissing on the FM radio signal is lost it will be found a strong and stable.
2.2 Inductor
2.3 Transistor
Transistors have two connections, one of which is the emitter and the other base and collector. Because this is a transistor as two diodes. ransistor C1970 type normally used to raise the voltage 0.8 to 1 watt, I think it was in the C1970 study could increase about 8 times.On the C1971 transistor can be coupled directly from the exciter circuit and the voltage of 6.5 to 7 watts or bias raised about 10 times.If the C1970 to C1971 join the output power of about 12 watts or more. (All will be explained in Chapter III)
Transistors have two connections, one of which is the emitter and the other base and collector. Because this is a transistor as two diodes. ransistor C1970 type normally used to raise the voltage 0.8 to 1 watt, I think it was in the C1970 study could increase about 8 times.On the C1971 transistor can be coupled directly from the exciter circuit and the voltage of 6.5 to 7 watts or bias raised about 10 times.If the C1970 to C1971 join the output power of about 12 watts or more. (All will be explained in Chapter III)
2.4 ExciterExciter circuit consists of an oscillator and buffer.• OscillatorTransmitter is the core of an oscillator. To be able to build a good communication system should begin with an oscillator that can work perfectly. In the communication system, the oscillator generates a sine wave is used as the carrier signal. Then the information signal is superimposed on a carrier signal with the modulation process.• Buffer (Buffer)All types of oscillators require a buffer. Buffer serves to stabilize the frequency and / or amplitude of the oscillator from loading the next level. Usually a buffer consisting of 1 or 2 levels of the transistor amplifier dibias as class A.The heart of the broadcast transmitter FM exciter is located on it. Function of the exciter is to generate and modulate a carrier wave with one or more input (mono, stereo, SCA) in accordance with FCC standards. Which has been modulated carrier wave is then amplified by a wideband amplifier to the level required by the next level.
2.5 BoosterPower amplifier is more popularly known as Booster. Booster is a device mounted radio transmitters attached to and used to amplify radio frequency transmit power in any direction that you want to go. For example, for a transmitter power of 25 watts which include only a single village, Booster is used to transmit power to be 50 to 100 watts so it can besurrounding the district. Boosters are generally small squares connected by cable to the transmitter which he built.Power amplifier is divided into two. First, the power amplifier which amplifies the signal in one cycle, the best signal quality and harmonious. The second, which only reinforces the power amplifier input signal is less than half of the cycle and generate a wave that damaged the same frequency.
Antenna function and simultaneously capture signals radiate radio wave radiation. The antenna is divided into two by the beam, ie• omnidirectional (all directions). This antenna radiates radio waves are equally strong all directions.• Bidirectional (both directions). This antenna radiates equally strong radio waves to only two directions. Two parameters that need to be considered is the polarization of the antenna and its gain. Put simply, an antenna has vertical polarization if the antenna is placed in a position perpendicular to the earth. Antenna with vertical polarization would produce radio waves with vertical polarization as well. In addition to the vertical, some horizontal polarized antenna, when the antenna is positioned parallel to the field of the earth.
2.7 Transmission LineTransmission line is the introduction to the generated power to the transmitter antenna. As an introduction to power, a good transmission line will not reduce the power of delivery and did not radiate, because it is the duty antennas radiate. So that the maximum power transfer occurs, then the transmission line characteristic impedance should also have the same view of resource load. Transmission line characteristic impedance is 300 W common (ribbon cable to the black and white TV), 75 W (on a color TV coaxial cable) and 50W (coaxial cable to the amateur radio equipment).Additional tools are in need in assembling a 12-watt FM transmitter, among which are:
• Power MeterPower Meter is a tool to measure the wave. On a transmission line that is not worth it, but the waves come rolling waves are reflected. Wave dating from the source to the load direction (from transmitter to antenna), while the reflected wave from the opposite direction (from the antenna to the transmitter). Usually on the Power Meter has two scales, onecame to power and one for the reflected power. The reflected power scale to be smaller than the scale for the future.
• SWR MeterSWR meter or measuring comparative standing waves are used to measure the ratio of the incident wave and reflected wave. So it is known how a resource commensurate with the burden. The working principle is based on the Power Meter SWR Meter. If there is only one Power Meter measurements, the SWR can be calculated from the incident power (Pf) andthe reflected power (Pr) with the formula:SWR = (OPF + ÖPr) (OPF - ÖPr).
• From the formula, the state equivalent (Pr = O) will be obtained SWR = 1.• For a state that is not worth going to get SWR> 1.
• For the worst circumstances in which all power is reflected back dating (Pf = Pr) will get the SWR = infinity.
• Dummy LoadTo be able to broadcast a maximum transmit power, but efficient, it takes a load impedance that is known with certainty as it is called Dummy Load reference. Dummy Load is free from the influence of frequency and can handle the disposal of the transmit power is too great. Dummy Load impedance is usually 50 or 75 Ohm. Dummy Load can be made withput some resistors in parallel in order to obtain the desired resistance and power. Parallelize some resistors minimize the stray inductance of the resistor. For example, can use the carbon resistor 300 Ohm / 2 watt for 6 seeds that are connected in parallel to get the Dummy Load with power of 12 watts and 50 Ohm impedance.
CHAPTER IIIPLANNING AND DEVELOPMENT TOOLS
3.1. PreliminaryTo plan and create a 12 Watt FM transmitter, need to know first about a block diagram of the system, the working system of the circuit isOverall, the calculations and planning.
3.2. System Block Diagram and Figure Series Overall
The picture above shows a block diagram of this system and imageThe overall network is made in full.Transmission System Block Diagram picture as a whole
3.2.1 Block diagram of the image transmitter exciter circuit FM
Picture Exciter Circuit Network consists of exciter oscillator and buffer. In this Exciter Network using the specification of components as follows:• Koker• Inductor: L2 = 0.12 micro-Henry, Henry Micro L3 = 0.12, L4 = 0.2 micro-Henry• Transistor: C930• Ohm: 5.6 K, 47 K, 33 K• Babysitter WANTED: 2.2 nF, 100 nF, 18 pF, 20 pF, 5 pF• trimer: 5-60 pFExciter is a network that produces oscillations, because the exciter are oscillator that acts as a sine wave generator and it will be dimodulasikan. In the oscillator system is also available buffer (buffer) that functions to stabilize the frequency / modulation oscillator amplifier due to the loading process by the next level.
3.2.2 Network Booster (Power Amplifier)
The series of images BoosterIn the Booster circuit uses components withthe following specifications:
• Inductors: L1 = 0.2 micro-Henry. L2 = 0.2 micro-Henry. 0085 L3 = L4 = 0.04 micro micro Henry Henry. L5 = 0.1 micro-Henry. L6 = 0.2 micro-Henry L7 = 0.2 micro-Henry.
• Transistor 1970: 10 V VCEIc 0.1 AΒ 10-180
• trimer: 5-30 pFBooster circuit consists of two levels of transistor amplifiers, each working on a class C, each input and output transistor amplifier circuit is given impedance adjustment.Strengthening of the first transistor using C1970. Strengthening the circuit has a 9.2 dB power gain (8 times), so that from the exciter-power 0.25 W of power generated should be 2 W. In fact the output of this first level of reinforcement produces only 1.75 Watt power, this is due to the loss of matching network circuit.Strengthening of the second level using transistor C1971. The amplifier circuit has a 10dB power gain (10 times). So that the power of the first level of 1.75 W can be strengthened to 17.5 W. In fact strengthening the power of the second level only reached 12.5 Watt.
This is due to the loss of matching network and the limited range ofC1971 transistor. Because the price of the C1971 transistor is relatively expensive it is to use only the C1970 transistor. Therefore, the power generated by the transmitter is not as high as 12 Watt. Because of the heat generated second transistor is large enough then we put enough cooling.
CHAPTER IVTESTING TOOLS4.1
GeneralThis chapter discusses the testing and analysis system that has been made. In general, this test aims to determine if the device has been realized that can be worked in accordance with a predetermined plan specifications. The purpose of the tests performed on the system are as follows:
• Knowing how the exciter circuit
• Knowing how the booster circuit
4.2 Testing exciter circuit
• The purposeTo find out if the oscillator can work well and achieve the desired frequency. And also to determine whether the buffer is running properly.
• The equipment usedA. Koker2. Inductor3. Transistor4. Resistor5. Trimer6. Dummy Load7. 5 volt power supply8. Multimeter9. Frequency Counter10. PCB
• The test procedureTest Block DiagramA. Assemble the equipment used in accordance Picture2. Provide 12 volt power supply to the exciter circuit3. Switch the exciter circuit to get the most power in large4. Calculate the voltage at TP 1, TP 2 and, TP 35. Observe the output (at V output)
• The test resultsThe test results are shown in Table. the following:Exciter circuit Testing ResultsTest Results PointA 0.6V2 0.6V3 11.75 V
4.3 Testing a series of booster
• The purposeTo gain greater power and also increase the distance range of further emission up to 7-fold.
• The equipment usedA. Inductor2. Transistor3. Trimer4. Dummy Load5. 12 Volt Power Supply
• The test procedureTesting Block Diagram Picture Booster:A. Assemble the equipment used in accordance Picture2. Large test circuit voltage that can be accepted3. Observing the output
• The test resultsThe test results are shown in Table. the following:Booster circuit Testing ResultsTest Results Point4 11,755 11,75
CHAPTER VCLOSING
5.1. ConclusionBased on the test results it can be concluded:
• In a series of FM transmitters weve made, the power output is only 2 Watt for C1970 transistor used is that only 1 Watt power up
• FM transmitter that can be made only reach 93 MHz frequency
• The distance achieved depends on the power emitted by the FM transmitter
5.2 Advice
• If you want to make the transmitter starts with a good oscillator.
• If you want to make a series of FM with a power greater then use the transistor C1971, C1946. the power generated about 25 watts.
• To balance the output of the FM transmitter mounted circuit PLL (Phase Local Loop).
Sunday, August 24, 2014
Build a Positive And Negative Voltage Switching Supply
Build a Positive And Negative Voltage Switching Supply. An LT1172 generates positive and negative voltages from a 5-V input. The LT1172 is configured as a step-up converter. To generate the negative output, a charge pump is used. C2 is charged by the inductor when D2 is forward-biased and discharges into C4 when LT1172`s power switch pulls the positive side of C2 to ground.
Positive And Negative Voltage Switching Supply Circuit Diagram
Saturday, August 23, 2014
The Reasons Why you should add a DVD Player to your Auto Sound System
When you are in the process of selecting your next auto sound system you might want to check out the systems that include other entertainment features such as games and DVD players. This may sound a little simplistic to some but if youve ever driven cross-country with children, you know what I mean when I say it is worth the investment to have one installed and have it installed correctly.
Many people will debate the wisdom of these devices and I will tell you quite frankly that I feel 100% that this is much safer than trying to deal with disgruntled children in the back that are literally fighting for your attention. If you want to talk about a distraction, I can think of few distractions that will top that while driving in holiday packed roads and less than favorable weather conditions. The truth of the matter is that anything that keeps the kiddies quiet for two hours at a pop has my vote for gadget or gizmo of the year.
I seriously recommend having a system installed however as this will limit not only the distraction to the driver but also the exposure of the lights and sounds to the driver as well. If you have a game system in stalled along with a DVD player and headphones to go with both I am sure you will find that you are driving along listening blissfully to your mom music as the kids in the back take turns playing games and watching DVDs. In fact, the most serious refereeing you are likely to need is over whose turn it is and how long that will last.
Now, I feel that it is very important to point out that this is not the only benefit to having an entertainment system installed for children that are traveling with you. Another very real benefit is the fact that you will also find that you are hearing less and less of the usual "are we there yet" and other generally disgruntled forms of questions from the backset. I also love the fact that the kids can often fall asleep to a DVD that they have seen a few dozen times which will bring a few more minutes of blissful silence as they snooze.
Another unexpected benefit I have found with my children and a DVD incorporated into an auto sound system is that my children are asking less often to stop for potty breaks. I always assumed that some of the frequent bathroom stops were boredom related and now Im fairly certain that my assumptions were correct. Another great thing that mommy does in order to keep things going smoothly is purchase a new DVD immediately prior to taking a long road trip. In addition to a new DVD that the little ones will not yet be tired of, I pull out some DVDs that might have been forgotten recently and not watched quite as often. This keeps the children very happy and quiet while mommy is able to concentrate on the road ahead and keeping everyone happy and safe while traveling.
Just remember that you should never rely on the scenery or the thrill of traveling in order to keep little ones happy and occupied on long trips. Endless questions and chatter are to be expected in order to alleviate boredom. In order to avoid these types of situations youll need more than happy music playing on the radio and really, how many times can you listen to "The Itsy Bitsy Spider" during a 12 hour road trip? Do yourself a favor when selection a really great auto sound system and make the necessary investment to add a really nice DVD player into the mix. Believe me I am the queen of cheap when it comes to trying to save money and will swear up and down that if you have children, this is one investment that is worth its weight in gold.
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