This circuit was obtained from a 1970s RCA. The circuit uses LDRs as sensors. The resistors depend on the A / D converter used. The circuit can be used as a shield.
This circuit has a low level at its output (pin 8) when the input signal has a frequency of 10...
Found in a 1993 Electronics Experimenter Handbook, this circuit uses a multimeter to measure...
The circuit is from an old American publication. We can mount it with the BC548 and TIP31. The...