I read in sci.electronics.design that Sam Goldwasser
wrote (in )
about 'Frost free / Auto defrost?', on Tue, 10 Aug 2004:

So you heat your food when the compressor isn't running?
'Heat' is a big word. It's about a 5 W heater embedded in the cooling
coil plate.

That forms an
oscillator with a frequency dependant on ambient temperature and the
quality of the fridge's insulation. I guess what you mean is that it
defrosts until another thermostat says there isn't any more ice.

No, just the one thermostat. It opens at about 0 C, stopping the
compressor, and the heater then warms up the plate to about 5 C, when
the thermostat closes again and cuts off the heat. I won't go to law on
the precise temperatures.
--
Regards, John Woodgate, OOO - Own Opinions Only.
The good news is that nothing is compulsory.
The bad news is that everything is prohibited.
http://www.jmwa.demon.co.uk Also see http://www.isce.org.uk