Using the 741 this circuit can be adjusted to values between 1 Hz and 100 kHz. The power supply must be symmetrical. We found it in the Radio Electronics magazine of November 1973.
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...