THEORY If an operator, instead of using an ON-OFF switch to control the power to the heaters, had a rheostat control, he would have much finer control of power to the furnace. Provided such things as outside temperature and amount of metal in the furnace are constant, he would be able to set the power level so that the temperature would remain at any desired level. The open loop configuration does not monitor or measure the ondition of its output signal as thereis no feedback.for example,an electric clothes dryer. Depending upon the amount of clothes or how wet they