| 摘要 |
PURPOSE:To attain miniaturization, mass-production and ease of adjustment with simple constitution by connecting a circuit of series connection of the 1st and 2nd transistors (TRs) in parallel with the 1st and 2nd capacitor to form a capacitance of a surface acoustic wave element and supplying a base voltage changed in response to temperature to the base of the 1st and 2nd TRs. CONSTITUTION:A base voltage is fed to a base of a TR26 via a resistor 19 and a thermister 28. A connecting npoint between the resistor 19 and the thermistor 28 is connected to common via a resistor 18. A base voltage is fed to a TR27 via a resistor 20 and the thermister 28. Further, a voltage fed to the thermistor 28 is kept to a constant voltage by a constant voltage diode 15 and the AC component is rejected by a capacitor 13. Since the termister 28 is a heat sensing element whose resistance is changed depending on ambient temperature, the base voltage or the TRs26, 27 is changed by temperature. Thus, the resistance value of the TRs26, 27 is changed by temperature.
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