This circuit was found in a 90s Popular Electronics. It generates tones given by the oscillators and can be changed. The circuit already includes an amplification stage.
We found this circuit in a 1966 US documentation. It simulates a variable capacitor that can vary...
In the figure we have the way to make the three-phase control of a motor using opto-diacs. The circuit is...
This low Power output stage can source a fraction of watt to a small loudspeaker. The transformer...