A system that controls our electric heater to keep the temperature of a room at some steady level, say, 25oC, is a common example of a regulator system. The set point can be adjusted from time to time that best suits current conditions. The circuit that is shown below is a fully automatic system. It can be easily used for controlling the temperature levels of an
- oven,
- a refrigerator,
- an incubator,
- a room or
- a building.
The temperature sensor shown by R1 is a thermistor. This is a part of a potential divider and the feedback signal is the voltages at the junction point of R1 and R2. In our diagram, this is labeled “t0”. It goes to the inverting input of the operational amplifier IC1, which is connected to play role of a comparator.
