PURPOSE: To increase the accuracy for detection of position, by securing a coincidence of characteristics among the transistors corresponding to plural energized voltage generating circuits in a numerical control system or the like and thus obtaining coincidence of wave crest value among the energized voltages.

CONSTITUTION: Singals SS1, SS2, SC1 and SC2 are applied to terminals S1, S2, C1 and C2, respectively, and thus the rectangular wave type energized voltages Ea and Eb having a difference of phase of π/2 are applied to primary windings 1a and 1b. Transistor TR1 of the 1st energizing circuit is opposite to the TR2 of the 2nd energizing circuit; and TR3 is opposite to TR4. Furthermore TR1 and TR2 plus TR3 and TR4 are formed on the same chip, respectively. As a result, good coincidence of characteristics can be obtained between the transistors in the same chip. Thus coincidence can be obtained for both the waveform and wave crest value between the voltages Ea and Eb to increase the accuracy for detection of position.