This is a compact adjustable power supply that delivers a stable voltage and currents up to 3 amperes. The circuit is very conventional and its voltage output can be varied from 1.25 volts to 25 volts.
The main module is the LM350 IC which integrates a voltage regulator and a power stage. It also has a built-in overload protection which activates at 30 watts of power dissipation. The voltage output is set by connecting the “adj” pin of the IC to the voltage divider made of R1 and P1. The output voltage can be calculated using the following formula: continue reading…

This power supply circuit is highly stabilized that its output voltage will drop only 0.005% even though the load changes from 0 to 100%. Another excellent capability is that the output voltage will change only by 0.01% if the input voltage fluctuates. The capability if the circuit to be adjusted from 0.1V up to 50V is due to the application of opamp IC CA3130 in the circuit. Transistor T4 raises the output voltage to higher level, and at the same time it separates the lower level opamp from the high level of the output voltage. The reference voltage is supplied by IC1. It is a temperature compensated transistor array with 5 transistors. Four of these transistors are used as reference diodes and the fifth one sets the output impedance of the reference source. continue reading…

This general purpose power supply can e used for supply output voltages from 1 to 35V. The line transformer should be selected to give about 1.4 times the desired output voltage from the positive side of filter capacitor C1 to ground. Potentiometer R2 sets the output voltage to the desired value by adjusting the reference input. continue reading…

This universal power supply contains, beside the bridge rectifier, a voltage stabilizer (78xx) and a pnp power transistor. This combination allow a load current up to 5 A. As you know a voltage stabilizer in a TO-220 package can deliver up to 1A. The additional power transistor takes the load current of about 200mA. continue reading…

This overvoltage protection or crowbar protection circuit is used where we need protection against high voltage surge. The circuit has a few components, it is very easy to build and will protect your electric equipment againg overvoltages. The crowbar circuit must be mounted between power supply and the protected device.
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