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.
The oscillator shown in the figure generates a 1 kHz tone that is reproduced on the speaker with...
In the figure we have the photo-conductive way of using a photocell to control a small motor with...
This circuit was found in the June 1991 issue of Radio Electronics magazine. The circuit uses two...