This interesting circuit uses a sodion valve that we have already described in an article on the website. The circuit uses several batteries for power. The phone is of high impedance.
This circuit drives symmetrical loads through a single transistor. The circuit is from a Radio...
The transistors of this circuit can be BC548 for NPN and BD136 for PNP with load up to 500 mA. The...
circuit is used to increase the sensivity of a relay. A 50 to 100 mA relay can be triggered with...