switch terminology

Thread Starter


Joined Feb 15, 2012
as part of an engineering course I am asked to design a new thermostat. The question is based more on the property change of materials and not so much to do with the circuitry, however my design has to include a switch that is activated (to start up the heating system) when a constant power source is stopped (due to the temperature dropping so low that a semiconductor stops conducting).

So basicly i just need to know the name of such a switch and possibly a few sentences describing it. just to recap i need a switch that is kept off when a power supply is running through/past it, but is turned on when the power stops.. thanks in advance!


Joined Mar 8, 2009
A relay should work. Use either a form B (SPST, normally closed) or form C (SPDT, use the normally closed contact) version.