Originally Posted by BrewmanBeing
How exactly are these used to control the temp of a common refrigerator?
You drop a probe into the fridge/freezer and plug the fridge/freezer into the controller's switched outlet. The controller cycles the fridge on/off to maintain temperature within a specified range. You can control the temp within a few degrees at any temperature between the fridge/freezer's lowest temp and the ambient room temp.
With a 2-stage controller, you can also add a heater in the fridge and reach temps above ambient room temp, which is useful if the fridge is in an unheated garage, for example.