This type of answering machine was common at the time this circuit was published. Using two tape recorders, it was published in the June 1986 issue of Radio Electronics magazine.
This circuit provides a power of the order of 2 W, characterized by high performance. The output...
This 12 V to 110 V inverter with 100 W was found in a 1977 Signetics manual. The transformer must...
The gain of this amplifier is given by the components indicated in the formulas next to the...