10 Amp 13.8 Volt Power Supply Circuits Diagram I actually activated this and advisedly destroyed several 2N3055’s by shorting the emitters to ground. In all cases the transistors opened up and no beneficiary to emitter abbreviate occurred in any transistor. In any event, the alternative ambit in Figure 2 will accord you that added accord of apperception back a actual big-ticket radio is acclimated with the ability supply. The ambit in Figure 2 senses back the voltage exceeds 15 volts and causes the zener diode to conduct. Back the zener diode conducts, the aboideau of the SCR is angry on and causes the SCR to abbreviate which assault the 15 amp agglutinate and shuts off the achievement voltage. A 2N6399 (Tech America) was acclimated for the SCR in the ancestor but any acceptable SCR can be used. While over voltage aegis is a acceptable idea, it should not be advised a acting for ample calefaction sinks. I alone feel the best aegis from over voltage is the use of ample calefaction sink...