Temperature Monitor
Circuit diagram:
Notes:
Using a thermistor in the position shown makes a heat activated sensor. A change in temperature will alter the output of the opamp and energize the relay and light the LED. Swapping the position of the< thermistor and 47k resistor makes a cold or frost alarm.
author: Andy Collinson
e-mail: anc@mitedu.freeserve.co.uk
web site: http://www.zen22142.zen.co.uk
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