This circuit was found in a March 1988 Radio Electronics. The voltage scale is set at R3. 19 LEDs are used in this indicator circuit.
This circuit provides a signal that is twice the frequency of the input signal. The circuit was...
Published by Philips in 1965 documentation, the sensor for this circuit is a common LDR. The...
The circuit shown in the figure can drive a motor (or other type of load) for a time interval that...