Proportional Controlling of Water Temperatures
V. Thiel, H. H. Harvey · Journal of the Fisheries Research Board of Canada · 1970
In the regulation of water temperatures, it is now possible to improve on the conventional thermostat and the power switch it operates. This may be done through the use of a thermistor and a proportional controller. The latter supplies power to the heater in proportion to the difference between the temperature set on the dial and that measured by the thermistor. The result is exceptionally good temperature control with a minimum of mechanical problems.