Hughes suggests this circuit in a 1968 documentation. The circuit uses old transistors that can be replaced with equivalents. MOSFET is the critical component of the circuit.
We found this circuit in an English documentation from the 60s. The integrated circuits are the...
This circuit was found in a 90s Popular Electronics. It generates tones given by the oscillators and...
This amplifier circuit applies its signal to an ordinary audio amplifier to pick up signals from a...