Showing posts with label voltage. Show all posts
Showing posts with label voltage. Show all posts
Wednesday, August 13, 2014
Voltage Converter 0 5v to 6v Circuit Diagram
This is a Simple Voltage Converter 0.5v to 6v Circuit Diagram. Conventional silicon transistors just cant operate at voltages less than about 0.7v. Old germanium transistors could be used, but those are hard to find these days and most are rather large in size. Some new n-channel MOSFET devices with very low gate-source threshold voltage can operate at quite low voltages. Ive been experimenting with various devices and came up with one electronic circuit (shown below), which demonstrates how to boost the low voltage from a single solar cell to a higher voltage.
Voltage Converter 0.5v to 6v Circuit Diagram
The key component in the circuit below is a cheap single logic device from Texas Instruments. It turns out that TIs 74AUC family of parts can work down to about 0.45 volts. I tried one of their single schmitt trigger parts and found I was able to make on oscillator function nicely at 0.5 volts. I then used a charge pump technique and a cheap NPN transistor to form a low power flyback converter.
This hobby circuit can produce about 6 volts at the output from a 0.5v input. The idea is to use this boost circuit to generate the higher starting voltage needed by a much more powerful DC to DC converter. Once started, part of the converters output could then be feed back to the input, to sustain converter operation. This is known as a "bootstrap" technique. In the future, I hope to post a circuit which can supply several watts of power from a 0.5v input voltage. This would be ideal for charging a battery using power from a single large solar cell or several smaller cells wired in parallel.
Drown By : Dave Jhonson
Friday, January 10, 2014
Low Power Voltage Reference Circuit Diagram
The Low Power Voltage Reference Circuit Diagram described below, is a special implementation of current source LM334. Characterized by a very small temperature coefficient metatholio output voltage and consumes only 10uA room temperature. This current fluctuates by a few uA, when the ambient temperature varies significantly. The positive rate of temperature change LM334 offset by the negative of the contact base emitter transistors has a direct thermal coupling with the integrated.
To achieve the lowest possible temperature coefficient, it is necessary to adjust the output voltage of 1,253 V source to the arrangement easily done through R1. From the moment you get the desired output voltage, you are advised to stuck P1 and after the count value, replace it with a constant resistance. The best indeed is to replace P1 with the R1, so you have fewer parts. Prefer metal film resistors and tolerance of 1% E96 series. Having as a given that the output voltage obtained from the pin configuration LM334, is expected to show a negative resistance value 3.8 KO.
The resistance A3 ensures that the output impedance will be equal to 400 W. Under these conditions, the current that can provide the source to the load to be connected to out of retained less than 5 Ma stability of the voltage source is more than satisfactory. By varying the input voltage from 5 V to 30 V, the change in output was only 0.6 mem (from 1.2530 to 1,2536 V). The change in the thermal coefficient is maintained at values ??less than 50 ppm / C, and if you worry a bit more to the setting of the circuit, you will see that quite easily reaches 5 ppm / C. The requirements of the original circuit current was only 9.8 mA at a temperature of 22C.
Low Power Voltage Reference Circuit Diagram
Monday, December 23, 2013
12KV High Voltage Generator
The hobby circuit below uses an unusual method to generate about 12,000 volts with about 5uA of current. Two SCRs form two pulse generator circuits. 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 circuit at the secondary of the trigger coil charges up two high voltage disc capacitors up to about 12KV. Although this circuit 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 circuit needs to be carefully wired with lots of space between components.
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The voltage doubler circuit at the secondary of the trigger coil charges up two high voltage disc capacitors up to about 12KV. Although this circuit 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 circuit needs to be carefully wired with lots of space between components.
Tuesday, October 8, 2013
SOFT START MECHANISM FOR L200 VOLTAGE REGULATOR ELECTRONIC DIAGRAM
SOFT START MECHANISM FOR L200 VOLTAGE REGULATOR ELECTRONIC DIAGRAM
Ic (constant current) is charge capacitor C, where Ic = Vsc/R.
The output reaches its nominal value after the time ton. Vo-Vsc=(Ic.ton)/C.
ton=C.[(Vo-0.45)/0.45].R = CVoR/0.45.
Vo follows the voltage in pin 2 at less than 0.45 volt. It is because voltage of more than 0.45 V can’t be produced between pin 2 and pin 5.
Wednesday, October 2, 2013
Ultra Low Drop Linear Voltage Regulator
This circuit is a Mosfet-based linear voltage regulator with a voltage drop of as low as 60mV at 1A. The circuit uses a 15V-0-15V transformer and employs an IRF540 N-channel Mosfet (Q1) to deliver the regulated 12V output. The gate drive voltage required for the Mosfet is generated using a voltage doubler circuit consisting of diodes D1 & D2 and capacitors C1 & C2. To turn the Mosfet fully on, the gate terminal should be around 10V above the source terminal which is connected to the DC output. The voltage doubler feeds this voltage to the gate via resistor R3. IC2, a TL431 adjustable shunt regulator, is used as the error amplifier. It dynamically adjusts the gate voltage to maintain the regulation at the output. With an adequate heatsink for the Mosfet, the circuit can provide up to 3A output at slightly elevated minimum voltage drop.
Trimpot VR1 is used for fine adjustment of the output voltage. The RC network consisting of R5 and C6 provides error-amplifier compensation. The circuit is provided with short-circuit crowbar protection to guard against an accidental short at the output. This crowbar protection works as follows: under normal working conditions, the voltage across capacitor C5 will be 6.3V and diode D5 will be reverse-biased by the output voltage of 12V. However, during output short-circuit conditions, the output will momentarily drop, causing D5 to conduct. This triggers the MOC3021 Triac optocoupler (IC1) which in turn pulls the gate voltage to ground. This limits the output current. The circuit will remain latched in this state and the input voltage has to be switched off to reset the circuit.
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Trimpot VR1 is used for fine adjustment of the output voltage. The RC network consisting of R5 and C6 provides error-amplifier compensation. The circuit is provided with short-circuit crowbar protection to guard against an accidental short at the output. This crowbar protection works as follows: under normal working conditions, the voltage across capacitor C5 will be 6.3V and diode D5 will be reverse-biased by the output voltage of 12V. However, during output short-circuit conditions, the output will momentarily drop, causing D5 to conduct. This triggers the MOC3021 Triac optocoupler (IC1) which in turn pulls the gate voltage to ground. This limits the output current. The circuit will remain latched in this state and the input voltage has to be switched off to reset the circuit.
Monday, September 2, 2013
Battery Voltage Indicator Using SN16889
This battery voltage indicator electronic project is designed using linear voltage indicator SN16889 (manufactured by Texas Instruments) or MC16889 (manufactured by Motorola). The circuit below allows lighting, depending on input voltage of one or more LEDs. Maximum voltage at which all LEDs light is adjusted using potentiometer P1 to 15 volts. D7 can be red LED indicates a battery voltage too high. D6 LED green indicates a correct value and the battery voltage LEDs D5, D4 and D3 yellow indicates a battery voltage too low.
Battery Voltage Indicator Circuit Diagram
Battery Voltage Indicator Circuit Diagram
Saturday, August 31, 2013
Digital AC DC Voltage Tester Circuit
Description
It is always necessary for engineers and technicians to test AC/DC mains voltages and continuity for any given circuit during breakdowns, the above mentioned circuit can be used as and sought of tester and can also check the continuity for you. all one has to do is that to touch the two probes at the required terminal of either live or an dead circuit
The unique design of the tester allows the circuit to work in both AC and DC without any mode selector switch.
When the probes A and B are short circuited voltage pin 1 goes a little below the threshold of the Schmitt trigger due to the voltage divider action of the resistor R1, R2 and VR1 This disables the gate of pin1 and due to this the transistor T2 goes into saturation while the transistor T1 is cut off therefore the green LED glows while the red segment goes off and the display will now glow as “C”
Circuit Diagram
VR1 is a miniature preset which is to be calibrated before use its calibrations are fairy simple, keep both the probes A and B short circuited and the preset VR1 at its minimum value and slowly increase the resistance value of the VR1 till the red LED glows OFF and only green LED glows
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