QUARTZ OSCILLATOR WITH CONSTANT TEMPERATURE BATH

PROBLEM TO BE SOLVED: To provide a quartz oscillator with a constant temperature bath capable of coping with a difference among ZTC (zero temperature factor point) temperatures at every quarts vibrator, resulting in no frequency fluctuation that is caused by fluctuation of ambient temperature.SOLUTION: In a constant temperature bath 10 that is heated with a heter H, a quartz vibrator H and a thermistor Th having a negative resistance temperature characteristic are provided. A transistor 15 that drives the heater H is controlled by the output of a differential amplifier 14. The thermistor Th is arranged between a power source voltage Vcc2 and the inversion input of the differential amplifier 14, and a resistor R1 for adjusting ZTC is provided between the inversion input and the grounding point. A resistor R3 is provided between a non-inversion input of the differential amplifier 14 and the grounding point, and a resistor R2 is provided between the power source voltage Vcc2 and a connection point 17. Between the connection point 17 and the non-inversion input, a resistor R22 and a resistor R23 having a positive resistance temperature characteristic for detecting an ambient temperature are provided in parallel. The resistors R21, R22, and R3 are used as the resistance for adjusting sensitivity, to prevent change in control target temperature which is caused by change in ambient temperature.