Found in an American publication, this circuit makes use of transistors from the time. Components can be changed according to desired characteristics.
This circuit of a 1978 American publication monitors a telephone line by triggering a relay. The...
When S1 is in 1, the circuit operates with of half the total power applied to the load. When in...
This power supply also has a fine adjustment feature. The transformer is 16 + 16 V with 3 A and...