| 摘要 |
PURPOSE:To compensate the temperature variation of the gain of a microwave amplifier using an FET by automatically supplying a fixed drain current and voltage between the drain and source to a FETTR of which source is earthed. CONSTITUTION:The drain and gate of the FETTR 1 of which source is earthed are connected to positive and negative power sources through resistors 5, 8, respectively and also connected to the emitter and collector of a bipolar TR4, respectively. A reference voltage lower than the voltage between the drain and source of the FET1 by the voltage between the base and emitter because of resistors 6, 7 is supplied to the base of the TR4. When the temperature is increased, current between the base and emitter of the TR1 is increased, so that the collector current is increased, the voltage between the gate and source of the FET1 is reduced and the drain current is increased. The gain of the FET1 is increased together with the increment of the drain current, so that drain reduction due to the rise of temperature can be compensated. |
