Showing posts with label build. Show all posts
Showing posts with label build. Show all posts
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.
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.
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.
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 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
Tuesday, August 19, 2014
Build a Low voltage regulators Wiring diagram Schematic
These Low voltage regulators Circuit Diagram short-schema protected regulators give 6, 7, and 9 V from an automobile battery supply of 13 V nominal; however, they will function just as well if connected to a smoothed dc output from a transformer/rectifier schema. Two types are shown for both positive and negative ground systems. The power transistors can be mounted on the heatsink without a mica insulating spacer thus allowing for greater cooling efficiency. Both diagram are protected against overload or short-diagram. The current cannot exceed 330 mA.
Under normal operating conditions the voltage across R2 does not rise above the 500 mV necessary to turn Q2 on and the schema behaves as if there was only Q1 present. If excessive current is drawn, Q2 turns on and cuts off Ql, protecting the regulating transistor. The table gives the values of Rl for different zener voltages.
Low voltage regulators Circuit Diagram
Monday, August 18, 2014
Build a Safe Opamp Wiring diagram Schematic
Build a Safe Op-amp Circuit Diagram. This is a Safe opamp schema diagram, In intrinsically safe applications, it is sometimes necessary to separate sections of schemary by resistors which limit current under fault conditions.
Safe Opamp Circuit Diagram
The schema shown provides an accurate analogue output with effectively zero output impedance, despite having resistors in series with the output. which is independent of RA and RB. The values of RA and RB should be chosen to achieve the desired current limiting, but note that a proportion of the voltage given at the op-amp output will be dropped across these resistors. Any type of op amp would be suitable.
Friday, August 15, 2014
Build a Parallel Loop Alarm Wiring diagram Schematic
Build a Parallel Loop Alarm Circuit Diagram. Two SCRs are used with two sensor loops. One loop uses series switches, the other loop parallel switches. When a switch actuation occurs, the SCR triggers.The alarm should be a non interrupting type.
Parallel Loop Alarm Circuit Diagram
Wednesday, August 13, 2014
Build a Switching Power Supply Wiring diagram Schematic
Build a Switching Power Supply Circuit Diagram. This is a Switching Power Supply Circuit Diagram. This low-voltage high-current output, switching de power supply is running off the 220-Vac input. In this schema, an ST2 diac relaxation oscillator, Q3, Cl, and the diac, initiates conduction of the output switching transistor Ql, the on-time of which is maintained constant by a separate tiring computation network consisting of Q2, C2, SUS, and SCR 1.
The output voltage, consequently, is dependent on the duty cycle. To compensate for unwanted variations of output voltage because of input voltage or load resistance fluctuations, an HllC wired as a linear-model unilateral PNP transistor in a stable differential amplifier configuration is connected into the galvanic ally isolated negative-feedback loop.
Switching Power Supply Circuit Diagram
The loop determines the duty cycle and hence the output voltage. Of further interest in this schema is the use of several low-current, high-voltage, 400V VvRM thyristors (Q2, Q3,) which are also used as pnp remote-base transistors. Short-schema protection is assured by coupling Ql collector-current feedback into the tum-off schemary via Rss·
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