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 programmable sound circuit was found in the July 1978 issue of Radio Electronics magazine. It uses an...
The circuit shown simulates a programmable unijunction transistor (PUT). Transistors may be common...
This simple test lets you measure zener voltage. The power must be higher than the diode tested...