The AD537 uses its two reference outputsâ€”one fixed at 1 V, the other of which varies with temperature (1 mV per Â°K). At
0Â°C, the 1-V reference multiplied by 0.273 will balance this voltage and produce a zero output. The scale in this circuit is 10 Hz/Â°C, Output from, as well as power to, the circuit, is fed via a two-wire twisted pair. A frequency counter is used as a readout.