I’ve been messing around with my fridge and was wondering how the thermostat worked in a more scientific perspective. There has to be some way it monitors the temperature?
I’ve been able to find a labeled image(imgur.com/a/sRMrJK2) of a thermostat but how does twisting the screw change the temp range?
Also, what is a “delay timer” and what is the purpose?
In: Engineering
One common type of thermostat uses a coil of flat metal that shrinks when it gets colder and expands when it gets warmer – when it expands far enough, the metal closes a contact which turns on the compressor to cool down the fridge. Then once it gets cold enough again, it shrinks again which disconnects the circuit and the compressor turns off. The clever part is that by turning the dial towards “colder” or “hotter”, you’re also twisting the coil to either make it bigger or smaller, so that the compressor will turn on and off at higher or lower temperatures than before.
A delay timer is additional circuitry that prevents the compressor from running too often, because if it does that, frost can build up and then the fridge has to be manually defrosted, which sucks – but hardly any modern fridges require manual defrosting unless it’s malfunctioning.
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