| 摘要 |
PURPOSE:To readily and accurately regulate an inverter circuit for varying the frequency of the output voltage in response to a detected temperature by regulating the detecting characteristic of a temperature sensitive resistance element circuit by varying the magnitude of a power source voltage applied to the circuit. CONSTITUTION:One end of a temperature sensitive resistance element circuit made of a series circuit of resistors 50, 51 and a thermistor 52 is grounded, and the other end is connected to a movable contact terminal 53a of a changeover switch 53. A temperature signal voltage obtained from a voltage dividing terminal of a temperature sensitive resistance element circuit is inputted to a positive side input terminal of an operational amplifier 35, and inputted to a negative side input terminal of an operational amplifier 54. The output of an operational amplifier 35 is inputted through an integrator and an operational amplifier 39 to a pulse generator 43. The detecting characteristic of a temperature sensitive resistance element is controlled by connecting the movable contact terminal 53a of a changeover switch 53 to a stational contact terminal 53b, a semifixed resistor 57 is regulated to obtain the same voltage as the output of the operational amplifier 54, and the switch 53 is then switched. |
