This sequential tone generator circuit was found in the July 1980 issue of Radio Electronics magazine. It uses well-known integrated circuits. The tones are generated by programming resistors.
Photoelectric cells can be used as sensitive light sensors. However, the low voltage they generate...
With the illustrated circuit we can run a DC motor in one direction or the other, depending on...
In this circuit the relay triggers on when light falls onto the sensor, a common LDR. Power supply...