This circuit uses a 6-bit A / D converter from Philips, and has its output compatible with most common microcontrollers. The temperature sensor is an LM334 that is connected to a constant current source, which must be adjusted by the 2.5 k ohm trimpot. And the 500 ohm trimpot determines the operating range of the sensor. Note that the circuit should be powered by 5V symmetrical source. This application is suggested by Philips Components (1970).