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Circuit Diagram 1 Circuit Diagram 2   Circuit Diagram 3 Description Even if the digital multimeters have dominated in a lot of applications, in the measurement, exist the need for existence of instruments of clue in various appliances, voltage and current, as in power supply or elsewhere. The circuits that give make this precisely the work, measure the voltage in terminal a circuit and the current that passes in his. The circuit does not present particular difficulties for somebody that has a small experience. The two circuits are the himself, with a small difference only in their input, when they have they measure voltage or current and in connection that concern decimal point [ dp ]. In the department of input IC1 and IC3, exist the CA3161E, that is a A/D Converter for 3-Digit Display. In the drive of Display IC2 and IC4, exist CA3161E, that is a BCD the Seven Segment Decoder/ Driver. As it appear in Fig.1, that concern the voltmeter in input [ + IN ], exist in series a what resi...

This 1.5 volt led fasher runs more than a year on a single 'd" cell and alternately flashes 2 LEDs at about a 1 second rate. The circuit employs a 74HC14 CMOS hex inverter that will operate at very low voltages (less than 1 volt). One section is used as a squarewave oscillator (pins 1 and 2), while the others are wired to produce a short 10mS pulse on alternate edges of the square wave so the LEDs will alternate back and forth. The output sections each use a capacitor charge pump to increase the voltage for the LEDs.  The circuit draws an average current of 800uA from the 'D' battery and the LED peak current is about 40mA with a fresh battery and drops to about 10mA as the battery voltage falls to 1.1 volts. The capacity of a alkaline 'D' cell is about 12 amp hours with a cutoff voltage of 1.1 so the circuit should run about 12/.0008 = 15000 hours or maybe 625 days, but I haven't verified that yet. The idea for this circuit came from a single 1.5 volt LED f...

Do you need high current power supply without heavy and expensive transformer? Then, this circuit would be great choice for you. This 13.8 Volt 20 A regulated transformer less power supply. 20A transformer is very-very expensive, large in size and very heavy in weight. This power supply capable in delivers around 20Amps at 13.8V. For lower currents, a separate current limiting output, capable of 15ma up to a total of 20A has been added. Let us see what we have got here. The power transformer should be capable to deliver at least 25A at 17.5 to 20V. The lower the voltage, the lower power dissipation. The rectified current will be ironed by the C1, whose capacity should not be less than 40.000uF, (a golden rule of around 2000uF/A), but we recommend up to 50.000uF. This capacity can be built up by several smaller capacitors in parallel. The base of this design is a simple 12V regulator IC 7812.

Power Supply in this article use a regulator that is composed of 2 pieces of NPN transistor. A transistor acts as a power regulator and a transistor again serves as a controller output voltage. Power Supply has an adjustable output with a range of 6-12 VDC. The part that serves as a power regulator is Q1 TIP31. Then the controller output voltage is a voltage divider composed of R3, R4, VR1 and R2 provide bias to the base of Q2 to Q1 mengentrol power regulator. In a series of power supply is mounted 5.1 V zener diode which serves to make the minimum limit the output voltage with Q2. Adjustable Power Supply with transistor circuit Power Supply With transistor circuit is quite simple and can be made with the PCB holes, so for those who want to try to directly mempraktikannya. May the power supply circuit can be useful for readers, especially for friends who need a power supply circuit with the regulator transistor.

The switching regulator power supply used LM2575-5.0 on this schematic. You can make the stable voltage by using the 3 terminal regulator like LM317. However, because the output electric current and the inputted electric current are the same approximately, the difference between the input electric power (The input voltage x The input electric current) and the output power (The output voltage x The output current) is consumed as the heat with the regulator. Because it is, the efficiency isn�t good. Data sheet for LM2575 SIMPLE SWITCHER 1A Step-Down Voltage Regulator http://www.national.com/pf/LM/LM2575.htm

The battery circuit scheme is designed as a source of constant voltage with negative temperature coefficient. Transistor Q1 (BD 140) is used as a temperature sensor. transistor Q2 is used to prevent the battery from discharging through R1 when electrical power is unavailable. Charging circuit is designed based on the LM350 voltage regulator IC. The output voltage of the charger can be adjusted between 13-15 V by varying the POT R6. LM350 will try to keep the voltage drop between the input pin and output pin at a constant value of 1.25V. So there will be a constant current flow through resistor R1. Q1 act here as a temperature sensor with the help of R6/R3/R4 components that are more or less controls the base current of Q1. As connection emitter / base of transistor Q1, the same as other semiconductors, containing the temperature coefficient of-2mV / ° C, the voltage output will also show a negative temperature coefficient. This one is just a factor of 4 large, because the variation of ...

The linear power supply, shown in the schematic, provides 0-30 volts, at 1 amp, maximum, using a discrete transistor regulator with op-amp feedback to control the output voltage. The supply was constructed in 1975 and has a constant current mode that is used to recharge batteries. Circuit diagram : 0-30 Volt Laboratory Power Supply Circuit Diagram With reference to the schematic, lamp, LP2, is a power-on indicator. The other lamp (lower) lights when the unit reaches its preset current limit. R5, C2, and Q10 (TO-3 case) operate as a capacitor multiplier. The 36 volt zener across C2 limits the maximum supply voltage to the op-amps supply pins. D5, C4, C5, R15, and R16 provide a small amount of negative supply for the op-amps so that the op-amps can operate down to zero volts at the output pins (pins 6). A more modern design might eliminate these 4 components and use a CMOS rail-to-rail op-amp. Current limit is set by R3, D1, R4, R6, Q12, R10, and R13 providing a bias to U2 that part...

Here is simple Electronic circuit project of 5 volt micropower regulator circuit. This micro power 5 volts DC regulator can be designed using few operational amplifiers and some other electronic parts. 5 Volt Micro-Power Regulator Circuit Diagram:   This 5 volt regulator is ideal for instrumentation requiring good power efficiency . Maximum load current is 10 mA , and can be increased by changing Q1 to a power transistor and proportionally increasing the set current of A2. This circuit accepts a wide input voltage range between 6.5 volt and 30 volts. Low power 3 terminal IC regulators typically draw 2mA to 5mA quiescent current compared to only 50uA with this discrete implementation.