| 摘要 |
<p>A crystal unit and a thermistor with negative resistance-temperature characteristics are housed in a thermostatic oven heated by a heater. A transistor driving the heater is controlled by an output of a differential amplifier, the thermistor is placed between a power supply voltage and an inverting input of the amplifier, and a first resistor used to adjust the temperature of a zero temperature coefficient point of the crystal unit is installed between the inverting input and a ground point. A second resistor is installed between the power supply voltage and a non-inverting input of the amplifier and a third resistor is installed between the non-inverting input and ground point. One of the second and third resistors is a resistor assembly made up of a plurality of resistance elements and one of these resistance elements is provided with positive resistance-temperature characteristics and adapted to detect ambient temperature.</p> |
