Protection circuit for TV receivers output transistor - protects transistor during tubes voltage overload arcing with diode across base-emitter

摘要

The protection circuit consists of a diode coupled in anti-parallel with the output transistor base-emitter junction. The transistor emitter is earthed over a low impedance series R.C. circuit and its collector is coupled over a resistor to the CRT of a television receiver. The overload element discharge path is located between the tube and earth. The diode prevents the effects (resulting from lead inductance) of the overload element discharge from appearing at the transistor emitter, which would happen if the diodes were absent despite the low impedance R.C. circuit.