| 摘要 |
PROBLEM TO BE SOLVED: To compensate temperature excellently over a wide temperature range even with a simple configuration. SOLUTION: When the temperature rises and the resistance of a thermister NTC2 decreases, a divided voltage of a power supply voltage Vcc2 by a resistor R6 is decreased, a base level of transistor(TR) Q2 is decreased and its collector level rises but the TR Q2 is saturated. After the saturation, since the resistance of thermisters NTC3, NTC4 respectively decreases attended with the temperature rise, the collector level is conversely reduced. Since the collector level is applied to a variable capacitor D2 as a reverse voltage, the capacitance of the variable capacitor D2 decreases as the temperature rises and then increases. The variable capacitor D2 acts like a load capacitance of a crystal vibrator X1 and has a characteristic reverse to a frequency versus temperature change in the crystal vibrator X1, then the temperature can be compensated.
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