PURPOSE: To obtain a linearizer of a simple constitution, by generating a frequency output proportional to the measured quantity through an oscillation loop consisting of a comparator, a one-shot circuit, a function voltage generating circuit, etc.

CONSTITUTION: A voltage Ei corresponding to the measured variate applied to non- inverting and inverting circuits of a comparator 1 and a function voltage Ef from a function voltage generating circuit 3 are compared in the comparator 1. When Ei is larger than Ef, a one-shot circuit 2 is connected in loop by the comparison output from the comparator 1, and generates a constant frequency output for a specified period of time. As a result, switches S1 to Sn in circuit 3 are set to ON and OFF, and the function voltages proportional to the first power, second power, ..., n-th power of the output frequency of the circuit 2 are outputted regardless of the power source fluctuations and temperature fluctuations, and a loop oscillation circuit composed on circuits 2,3, etc. at a period to cause the voltage Ef to be equal to the voltage Ei oscillates, so that the frequency output at the period proportional to the measured variate is generated at the specified pulse width from a transistor Tr. Thus is obtained a linearizer having a simple constitution not requiring compensation for temperature and power source voltage.