Active three-tone filter (CB20808E)

This circuit was found in an American documentation and can be added to common amplifiers of any type. The transistor can be any general purpose.

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1kHz Triggered Oscillator 555 (CB25513E)
We found this circuit in the October 1992 Radio Electronics magazine. The frequency is given by C1...
PNP Mini Flasher (CB17511E)
This conventional LED flasher circuit has a configurable multivibrator configuration with PNP...
1-cycle-per-30-day oscillator (CB26073E)
This extremely slow circuit produces one pulse per month and can be used in a timer. We found it...