25 kHz Lowpass (CB25000E)

We found this circuit with the CA3140 in October 1986 Radio Electronics magazine. The circuit can be modified to operate at other frequencies.

Tuning Indicator (CB16620E)
This circuit must have its input connected to the collector of the last IF transistor of the FM...
Excitation of Various LEDs (CB16680E)
We found this circuit in a Texas Instruments Opto Electronics manual from 1992. In it we have the...
Electronic Bell (CB16470E)
In reality, it is an audio oscillator that is triggered by a structure that forms a bell-shaped sensor....