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.
In the figure we have the way to obtain an operational amplifier with FETs at the input, using a...
This circuit was found in a 1980s documentation. The low voltage circuit uses a PUT. Transistors can...
This circuit shows numbers I II and III when mounted on its side, depending on the position of the...