Using a pair of period A/D converters, this 3-digit circuit was found in the 1992 Radio Electronics Experimenter magazine. The sensor is a thermistor.
This frequency modulated light transmitter is from a 1990s documentation. The circuit may use...
The basis of this circuit is an LM380 that drives a speaker that emits sound when moisture is...
This precision circuit can provide timings from 0.2 milliseconds to 3 minutes accurately. The...