This circuit has a frequency range of 30 Hz to 100 kHz with an output signal of 1 Vrms. We found it in 70s American documentation. The integrated circuits are CA3140.
This circuit is from an 80's electronic component manual. It has the way to simulate an inductor...
This is the receiver for the previous circuit found in the November 1991 Radio Electronics...
This circuit was found in a Popular Electronics documentation from the 90s. It is possible to switch...