Sophisticated pulse proportional thermostat, ideal for controlling higher power ceramic heaters. The function of this thermostat is far more sophisticated than the simpler on/off switching devices. It will very accurately control heaters and has a maximum load of 600 watts. A normal thermostat switches a heater on full power until the set temperature is achieved. It then switches the heater off completely until the temperature drops below the set value, when the cycle starts over again. The gap between the heater being switched on and then off is called hysteresis. It is between these points that the accuracy of the controller is assessed. The pulse proportional thermostat pulses electricity to the heater.

The sequence of events are as follows: The temperature is set on the dial. The cage and heater are cold so the heater is on full power.As the temperature in the cage nears the set temperature the unit cuts the power down to pulses.The degree of pulse (i.e. the ammount of time the heater is on and the ammount of time it is off) is dependent on the cage temperature. In the early stages of approaching the set temperature the 'on' pulses will be long and the 'off' time will be short. In a correctly set up cage, as the desired temperature is neared, the 'on' pulses become shorter until the cycle levels at approximately 50% on and 50% off. In a cage where the heater is of the correct capacity, the cycle should remain at this point. The heater is only powered enough to maintain the temperature set. It does not have to continually start the heater from cold. This vastly improves heater element life and is far safer for the animals as the heater rarely, if ever, needs to run at full power.