This circuit with germanium transistors was found in a publication by Gernsback from 1960. The circuit is low power, a few tens of milliwatts.
This car alarm was obtained in a Signetics documentation from the 1980s. The circuit uses the 555...
The frequency of this circuit can be varied from zero. The circuit uses the CMOS 4046 and was...
This simple binary counter triggers two LEDs according to the number of pulses applied to the...