Forum Diagram: voltage

Showing posts with label voltage. Show all posts

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.

Tuesday, October 28, 2014

Voltage Feedback Op Amp

VOLTAGE FEEDBACK OPERATIONAL AMPLIFIER
Device Description:
Voltage feedback operational amplifiers usually manufactured for industrial use have ultra-low power requirements, with a typical quiescent current value of approximately 250 micro amperes. The typical current drawn in powered-down mode for such an amplifier is 0.5 micro amperes. They are suitable for operation at any bandwidth below 56 MHz. The manufacturing process is called a SiGe complimentary bipolar process. It is an advanced method used at the industrial level.
Ultra-low power-op amps have rail-to-rail output along with negative rail input. They are specially designed to operate under an EMF ranging from 2.5 – 5.5 Volts. There are two options: the single or dual supply operational amplifier. The aforementioned voltage supply is for single mode op amps whereas for a dual mode operational amplifier the power supply ranges from -1.25 to -2.25 Volts and 1.25 to 2.75 Volts (in dual supply configuration). These operational amplifiers are leading the industry due to their high power/performance ratio. They consume a mere 250 micro amperes of current on each channel, under a unity gain of 56 MHz.
A voltage feedback operational amplifier is well-suited for portable battery applications in which low power consumption is desired along with good performance. It consumes little power, yet offers high frequency performance. Such operational amplifiers serve as the device with high frequency performance in many battery-powered applications by lowering current consumption. This is achievable on account of a power saving mode, in which its current consumption can be lowered to 1.5 micro amperes. A voltage feedback operational amplifier consists of an integrated gain setting resistor in its both single and dual supply variants. These gain setting resistors are bound to a printed circuit board with the smallest possible size across a wide range of attainable gain values - they can be replaced with a potentiometer for controllable resistance. The design of a voltage feedback operational amplifier impacts the range of attenuation values. These amplifiers are designed to work at industrial-standard temperatures ranging from -40 to 250 degrees centigrade.
Applications of Voltage Feedback Operational Amplifiers
A voltage feedback operational amplifier has many industrial applications, including the following:
•    Audio ADC input buffers
•    Portable systems
•    High density systems
•    Low power systems
•    Ultrasonic flow systems
•    ADC Drivers
•    Low power SAR
•    Low power signal conditioning systems.

Sunday, October 5, 2014

Step Up Input Voltage DC DC Converter

Step Up Input Voltage DC-DC Converter Circuit

This circuit uses bog standard parts, without requiring a magical "do-it-all" IC. You can make an ultra simple 1.5v to 9v regulated stepup converter by using a TL496 IC, a coil and a capacitor, but thats not so much fun if you want to experiment. Ive already built a TL496 based circuit so I started doing web searches for something that I could make that would allow more fiddling and a wider range of applications.

Thursday, October 2, 2014

How to Generate Stepped Voltage Circuit Diagram

This circuit converts an input signal into one that is composed of a number of discrete steps but which re- mains otherwise identical to the input signal.
Because the steps are of equal height, the harmonic con- tent of the output signal will be dependent upon the amplitude of the input signal. This chararacteristic is extremely useful in the making of electronic music. The circuit uses quantitised pulse- width modulation for the adding of the step—shaped input signal. Pulse-width modulation is obtained by comparing a triangular voltage with the analogue input signal by means of a comparator; the quantitising, that is the adding of the steps, takes place by replacing the triangular voltage with a stepped l voltage.

The stepped-voltage generator con- l sists of three gates, N1 . . . N3 and transistor Tl. N1 operates as an astable multivibrator, that oscillates at a frequency depending on the value of Cl and Rl. Transistor stage T1 fu nctions as a charger circuit: each time the output of N1 is logic l, the transistor transfers the charge on C2 to capacitor C4. During the next half cycle C2 is recharged via Dl. ln this way the voltage across C4 increases in discrete steps, the height of the steps being deter- mined by the ratio C2:C4. When the voltage across C4 rises above a certain value, N2 switches transistor T2 on via gate N3 and discharges capacitor C4. When the capacitor is completely discharged, N2 switches off T2 and C4 continues to charge again in discrete steps The stepped voltage is set to the inverting input of lC2 which is connected as a comparator.

Low- pass filter R4/C7 in the output of lC2 converts the pulse-width modu- lated signal back to an analogue one. The d.c. voltage level at the non- inverting input is set by potentiometer P2 to half the magnitude of the stepped voltage. The setting of P1 is dependent upon the input signal which must be attenuated such that the maximum value at the slider of P1 is always smaller than the maximum value ofthe stepped voltage. The number of steps can be selected by varying the value of C4. lt is possible to use a varicap in place of C4 with the varicap voltage being controlled by the music program or the input signal. Interesting and individual effects can be obtained in this way.

Tuesday, September 16, 2014

Fixed Voltage Power Supply

The fixed voltage power supply is useful in applications where an adjustable output is not required. This supply is simple, but very flexable as the voltage it outputs is dependant only on the regulator and transformer you choose. The maximum output current is 1.5A. Fixed Voltage Power Supply Circuits diagram : Parts : Part Total Description C1 1 2200uF 35V Electrolytic Capacitor C2, C4 2 0.1uF Ceramic Disc Capacitor C3 3 10uF 35V Electrolytic Capacitor

D1, D2 1 1N4007 Silicon Diode

BR1 1 2A 30V Bridge Rectifier

U1 1 Regulator (See Notes) T1 1 Transformer (See Notes) S1 1 SPST 2 Amp Switch F1 1 2A 250V Fuse and Holder Misc 1 Heatsink For U1, Line Cord, Case, Wire

Notes :

Since this project operates from 120 (or 220, or 240, etc.) volts AC, it MUST be built inside a case.
U1 will reauire a heatsink.
You will need to choose T1 and U1 to match the voltage you want. Use the table below as a reference.

Thursday, September 11, 2014

Digital Mains Voltage Indicator

Digital Mains Voltage Indicator Circuit diagram. Continuous monitoring of the mains voltage is required in many ap-plications such as manual volt-age stabilisers and motor pumps. An ana-logue voltmeter, though cheap, has many disadvantages as it has moving parts and is sensitive to vibrations. The solidstate voltmeter schema described here indicates the mains voltage with a resolution that is comparable to that of a general-pur-pose analogue voltmeter. The status of the mains voltage is available in the form of an LED bar graph. Presets VR1 through VR16 are used to set the DC voltages corresponding to the 16 voltage levels over the 50-250V range as marked on LED1 through LED16, respectively, in the figure. The LED bar graph is multiplexed from the bottom to the top with the help of ICs CD4067B (16-channel multiplexer) and CD4029B (counter). The counter clocked by NE555 timer-based astable multivibrator generates 4-bit binary ad-dress for multiplexer-demultiplexer pair of CD4067B and CD4514B.

Digital Mains Voltage Indicator Circuit diagram

Digital Mains Voltage Indicator Circuit Diagram

The voltage from the wipers of pre-sets are multiplexed by CD4067B and the output from pin 1 of CD4067B is fed to the non-inverting input of comparator A2 (half of op-amp LM358) after being buff-ered by A1 (the other half of IC2). The unregulated voltage sensed from rectifier output is fed to the inverting input of com-parator A2. The output of comparator A2 is low until the sensed voltage is greater than the reference input applied at the non-inverting pins of comparator A2 via buffer A1. When the sensed voltage goes below the reference voltage, the output of com-parator A2 goes high. The high output from comparator A2 inhibits the decoder (CD4514) that is used to decode the out-put of IC4029 and drive the LEDs. This ensures that the LEDs of the bar graph are ‘on’ up to the sensed voltage-level pro-portional to the mains voltage.

The initial adjustment of each of the presets can be done by feeding a known AC voltage through an auto-transform and then adjusting the corresponding pre-set to ensure that only those LEDs that are up to the applied voltage glow.

EFY note. It is advisable to use ad-ditional transformer, rectifier, filter, and regulator arrangements for obtaining a regulated supply for the functioning of the schema so that performance of the cir-cuit is not affected even when the mains voltage falls as low as 50V or goes as high as 280V. During Lab testing regu-lated 12-volt supply for schema operation was used.)

Author : Pratap Chandra Sahu - Copyright : EFY

Wednesday, September 3, 2014

Multiplier Single Pulse Voltage Circuit

Single Pulse Voltage Multiplier
Obtaining higher voltage pulses without a higher voltage power supply

Originally appeared in EDN/Reed Business Information September 18, 2003

Sometimes its necessary to generate a higher voltage pulse from logic diagram than the diagram themselves can supply. The need to generate a programming pulse for Atmel flash controllers was one of those. In that case, I needed to generate an infrequent pulse that switched from 5 volts to 12 volts in response to a control signal from a microcontroller.

A method that relies on a pushbutton to double the voltage was used in the ATtiny12 fuse restorer, but there, the generation of the +12 volts was done by using a mechanical switch that was manually operated to generate about 18 volts, which was further regulated to +12 volts by a gated regulator. It was good as far as it went, but the generation of the +12 volts could not be triggered by the microcontroller, that is unless one wanted to use an electromechanical relay or elaborate arrangement of switching devices.

The straight-for ward approach to control by a microcontroller could be accomplished by driving a capacitor voltage multiplier (such as in the Seiko display inteface) with a pulse train from a controllers pin, then regulating and switching the resultant voltage, the drawback being that this took a lot of parts.

The schema below accomplishes the same result. It still uses a transistor to do some switching, and it still needs a pair of diodes and capacitors, as would be used in a conventional multiplier, but it doesnt require a steady stream of pulses and the output voltage is set by a resistor divider as the 100k and 150k resistors make 2 volts that are added to the 10 volt pulse on the transistors collector. What it doesnt need is a steady stream of pulses to keep the output voltage pumped up all the time.
The basic multiplier cell was inspired by a discussion I had with a well know laser scientist, Mr. Christoph Krah, about laser triggering diagram. After I finished this schema, I sent it to Mr. Krah to get his opinion of how this schema related to some of those we discussed years ago. Here is Mr. Krahs taxonomic analysis, which also includes a concise description of schema operation which I could not improve upon:

"Your schema seems to be a combination of a Marx and a Cockroft-Walton type multiplier. You charge capacitors in parallel (100uF @ 5V and 100uF at 2V) and then switch them in series by means of a 5V voltage step (5+5+2 = 12V) at the output of the uC. The diodes provide isolation from the power supply."

For many of applications, the diode on the left side can be omitted and the 1k resistor changed to 100k.. This simplifies the schema at the cost of slightly increasing the rate of droop of the voltage across the first 100 uf capacitor since it will discharge into the 100k resistor as well as driving the base resistor for the transistor and driving the load and 100k/150k voltage divider.

There is no free lunch with this schema. If the pulse is initiated before the 150k AND 100K resistors charge the 100 uf capacitor sufficiently (60k x 100 uf = 6 seconds), the output voltage will be lower than intended. The charge time of the schema can be decreased by reducing the values of the capacitors, the output 100 uf capacitor having the most effect because of the high resistance charge path. Reducing the size of the capacitors will make the output pulse droop more quickly.

It should be noted that this schema also makes a 0 to 10 volt pulse, which appears on the collector of the transistor. If a 0 to 10 volt pulse is desired, the schemary to the right of the transistors base resistor may be omitted.

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

High Voltage Pulse Supply Wiring diagram Schematic

This high-voltage pulse supply will generate pulses up to 30 kV. Ql and Q2 form a multivibrator in conjunction with peripheral components Rl through R6 and CI, C2, C3, C5, C6, and D2. R9 adjusts the pulse repetition rate. R2 should be selected to limit the maximum repetition rate to 20 Hz. II is a type 1156 lamp used as a current limiter.

R9 can be left out and R2 selected to produce a fixed rate, if desired. Try about 1 as a start. Q3 serves as a power amplifier and switch to drive Tl (an automotive ignition coil). NE1 is used as a pulse indicator and indicates schema operation. Because this schema can develop up to 30 kV, suitable construction techniques and safety precautions should be observed.

High-Voltage Pulse Supply Circuit Diagram

Monday, August 18, 2014

Maximum Minimum Voltage Indicator

This schema indicates which of three voltages in the range from about about -4V to about +4V - at A, B and C - is the highest by lighting one of three indicator LEDs. Alternatively, it can be wired to indicate the lowest of three voltages or to indicate both the highest and lowest voltages. Op amps IC1a, IC1b & IC1c are wired as comparators, while the three indicator LEDs and their series 1kO current limiting resistors are strung across the op amp outputs to implement the appropriate logic functions.

Maximum Minimum Voltage Indicator Circuit diagram:

Maximum Minimum Voltage Indicator Circuit Diagram

For example, LED A will light only when pin 8 of IC1c is low (ie, A greater B) and pin 7 of IC1b is high (ie, A greater C). Similarly, LED B will light only when pin 8 of IC1c is high (ie, B greater A) and pin 1 of IC1a is low (ie, B greater C). LED C works in similar fashion if the voltage at C is the highest. Note that if all the LEDs and their parallel 1N4148 diodes are reversed, the schema will indicate the lowest of the three input voltages. And if each 1N4148 diode is replaced by a LED, the schema will indicate both the highest and lowest inputs.

Author: Andrew Partridge - Copyright: Silicon Chip

Saturday, August 16, 2014

12KV High Voltage Generator

The hobby schema below uses an unusual method to generate about 12,000 volts with about 5uA of current. Two SCRs form two pulse generator diagram. The two SCRs discharge a 0.047uF a 400v capacitor through a xenon lamp trigger coil at 120 times a second.

The high voltage pulses produced at the secondary of the trigger coil are rectified using two 6KV damper diodes. The voltage doubler schema at the secondary of the trigger coil charges up two high voltage disc capacitors up to about 12KV. Although this schema can’t produce a lot of current be very careful with it. A 12KV spark can jump about 0.75 of an inch so the electronic schema needs to be carefully wired with lots of space between components.

Source: DiscoverCircuits

Friday, August 15, 2014

High and Low Mains Voltage Cut Off Wiring diagram Schematic

High and Low Mains Voltage Cut Off Circuit

Are you having problems with your input Mains supply? That’s common problem associated with our input mains AC line, where a high and a low voltage conditions are quite frequently encountered by us. The simple schema shown here can be built and installed in you house electrical board for getting a 24/7 safety from the possible dangerous AC voltage conditions. The schema keeps the relay and the wired appliances as long as the mains input stays within a safe tolerable level and switches the load OFF the moment a dangerous or unfavorable voltage condition is sensed by the schema.

Parts List

R1, R2 = 1K,

P1, P2 = 10K Preset,

T1, T2 = BC547B,

C1 = 100uF/25V,

D1 = 1N4007

RL1 = 12V, SPDT,

TR1 = 0-12V, 500mA

Thursday, August 14, 2014

Simple Micro Inverter circuit DC voltage AC 12v x110v

This is a micro-inverter DC voltage to AC from a 12v battery can generate a voltage of 110 or 220 volts AC and a frequency of 50Hz to 60Hz. The schema is very simple and does not need a printed schema board, It is composed of two transistors oscillators that generate the square wave pulse to the transformer in the case is 10 +10 and its output 220V or 110V. This schema is 50Hz, but can be changed by changing the value of RC .

Micro Inverter schema DC voltage AC 12v x110v Circuit Diagram

This schema has the power transistor and that depends on the transformer.

Simple Micro Inverter schema DC voltage AC 12v x110v