- Published in issue 12/1993 on page 50
The monttor is intended for use in relatively small spaces (like living rooms). The sensor is a readily available LM335 from National Semiconductor. This gives an output voltage of 10 mV °C^-1. This voltage is compared in IC(1a) and lC(1b) with two reference voltages. One of these is preset with P1 and the other with P2. The output of the comparators is used to switch D2, D3 and D5.