The lamp dimmer just increases/decreases the amount of electricity running into the heat source. With a thermostat with a probe you place the probe in at the warm side and set the thermostat to whatever temp you want the warm side at then once the air temp gets to be the set temp the heat product turns off then when it cools down it turns on. Therefore making the temp at a constant set level. There are lots of people who use both a thermostat and dimmer with flexwatt because of a malfunction of one/other. If you have a lamp dimmer and the room temp goes up 5 degrees so does your cage.
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0.1 Albino Leopard gecko (Lex)
0.0.1 ball python (felix)
1.1 feral cats (Fuzzy, and Bear; it used to be fuzzy, wuzzy, bear)