Based on the 4017 integrated circuit, this circuit of a European 303 Circuits from the 90s, generates a pulse train in a relay that mimics the dialing of a telephone.
The signal from this circuit found in a 1968 Electronics World is sinusoidal and depends on the...
This circuit uses a sensitive vibrator that can be made with a reed-switch to activate a relay from...
This amplifier can be powered with voltages between 2 and 5 V with power up to 100 mW. The minimum...