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What is a Thermostatic Switch?

Alexis W.
Alexis W.

A thermostatic switch is a power switch powered by the device it controls, through either the thermal conductivity or the thermal convection of the device itself. Thermostatic switches, in essence, are controls that operate solely on the information given to them by measuring the temperature emitted from the device they control. When a setting for the switch is created, the switch either engages the device or disengages the device when the set temperature is reached. This creates a low-maintenance thermal device, as it doesn’t require the user to operate the power switch; it simply turns off when the desired temperature is reached.

One of the instances where a thermostatic switch is typically utilized is inside an electric oven. The user sets the temperature of the oven on the dial or digital faceplate of the oven, and the oven engages. When the desired temperature is reached and the thermostatic switch senses this, it automatically disengages the oven burner so the desired temperature isn’t exceeded. Once the burner is disengaged, the temperature is allowed to vary slightly before the switch re-engages the burner in order to maintain the desired temperature.

There are also many instances where the user operates the thermostatic switch directly. One such example is the in-home thermostat. There, the switch automatically engages and disengages the heating unit once the user sets the desired temperature.


Thermostatic switches can also be used as a means of protecting electrical devices. For instance, the circuit board, or motherboard, of a computer has many elements in it that generate an amount of heat that could very easily damage the circuit, rendering the computer useless. Thus, a thermostatic switch is employed within the system to regulate the air flow into and out of the computer casing by engaging a cooling fan any time a certain temperature inside the casing is reached. The thermostat in a vehicle’s engine is also responsible for the engagement of the fan, which cools it by drawing fresh air through the radiator system whenever the temperature of the engine reaches a specific level designated by the engine’s specifications.

In order for an automatic thermostatic switch to function properly, it must be programmed to have a designated on/off temperature range. This means that two separate temperatures are needed to tell the switch at what point to engage the device and at what point to disengage it. Once the temperatures are programmed, the switch can function without user input.

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