This circuit operates from 20 Hz to over 20 kHz and is easily tunable. We found it in a 70s documentation. The circuit can be implemented with modern operational amplifiers.
The simple touch of the fingers on a sensor causes this circuit to drive a motor that goes into...
This simple circuit found in an American 80's documentation simply blames if there are toxic gases in...
This circuit is from Motorola's 1990 Linear Databook. The transistors allow equivalents and the...