We found this circuit in an 80's manual. The same configuration can be adapted to make use of modern operational amplifiers. The power supply is symmetrical.
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...