A simple, inexpensive, square-law circuit
Arthur Edmunds, K. Slater · Journal of Scientific Instruments · 1966
Using a silicon carbide nonlinear resistor which is readily available commercially in a series combination with a suitably chosen fixed resistor, a simple and inexpensive square-law circuit which has adequate accuracy for some applications can be made. Satisfactory temperature compensation can be obtained by using the correct, commercially available thermistor as part of the fixed series resistor.