This old voice circuit suitable for telephones of the time was found in a Radio Electronics from September 1973. The circuit is powered by a voltage of 7 V.
This circuit is from an 80's documentation. The transistor can be any general purpose PNP and the...
This powerful pushbutton uses a power MOSFET. We found it in a Popular Electronics magazine from...
This shield circuit for lamps and other charges was found in a Popular Electronics from the 90's....