This circuit with a bargraph scale was found in a 90s Popular Electronics. The circuit measures the intensity of a sound in three scales. R14 works as a sensitivity adjustment.
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...