This variable frequency circuit was found in a Popular Electronics from the 90s. The circuit outputs to a small speaker and can be powered by voltages as low as 3 V.
The Schmitt-trigger shown in the figure is TTL compatible and is shown in the figure using...
We found this circuit on Motorola's Linear Interface ICs. The components are current, and the...
With two cascading tunnel diodes, this circuit found in a 196 General Electric documentation...