Switch-Triggered Flip Flop (CB25674E)

This two-transistor circuit was found in the January 1994 issue of Electronics Now. The circuit can be powered by voltages from 3 to 12 V.

Power grid powered metronome (CB7289E)
This circuit from an old documentation includes the power supply for the 117 V power grid. It can be...
Voltage comparator oscillator (CB5972E)
The frequency of this circuit is approximately 1 Hz. Whenever the output is at low level, the LED...
Crystal Tester (CB3881E)
This circuit has been found in an old documentation and therefore uses a lamp as an indicator. In a...