| 摘要 |
PURPOSE:To compensate sufficiently the fluctuation of a power supply voltage and a change of temperature by using a potential difference between the collector and the emitter of a transistor (TR) for bias as a bias voltage of an amplifying or oscillating TR to set optionally the bias voltage of the amplification TR. CONSTITUTION:The bias voltage of the amplification TR 3 is set mainly by a potential difference between the collector and the emitter of the bias TR 14 and the potential difference of the TR 14 is adjusted by resistors 15, 16. Thus, the bias voltage of the TR 3 is set optionally by the resistors 15, 16. The potential difference between the base and the emitter of the TR 14 is decreased similarly by the decrease in the potential difference between the base and emitter of the TR 3 due to the temperature rise, the base current is increased and the collector-emitter potential difference is lowered. As a result, the bias voltage of the TR 3 is decreased and the collector current is kept constant. If the bias voltage is going to rise by, e.g., the rise of the power voltage, the base current to the TR 14 is increased, the impedance is reduced and the collector-emitter voltage is kept constant. Thus, the bias voltage of the TR 3 is kept constant.
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