3A Universal Power Supply

This universal power supply is universal in the true sense. With a output continually variable from 1.25 volts to 25 volts, this power supply is left with hardly any needs that it can't fulfill.The power supply is short circuit protected and  has in-built thermal overload protection.

As shown in figure, the power supply uses an LM350 type variable regulator. The IC in a TO-3 package and resembles the common 2N3055 and AD149 transistors. VR1 provides voltage control.R1,D2 and C2 are the accompanying components. The input voltage is obtained from an 30 volt source such as a transformer etc. The diode D1 provides a path for C3 to discharge  when the power is turned off. The output wires carry heavy currents, so adequate care must be taken to ensures the use of thick wires and terminal to prevent failures.A standard transistors type heat-sink must be used.