Found in a Popular Electronics from the 90s, this circuit is intended to measure the harmonic distortion of an audio signal. The circuit can be tuned between 970 and 1030 Hz.
The search coil of this detector consists of 140 turns of wire 18 in an 8 inch diameter form. The...
This circuit was obtained from a 1966 General Electric documentation. It can serve as a basis for...
The quiescent current of this alarm is in the order of microamps and the same is true for the...