| 摘要 |
A biasing circuit is provided for stabilizing the gain of a transistor amplifier against variations in temperature. The amplifier includes an input terminal and a transistor having a base-to-emitter junction coupled between the input terminal and the second terminal of a two-terminal source of supply potential. The biasing circuit is coupled between the two supply terminals and includes a resistor coupled to the first terminal, a semiconductor rectifying junction coupled between the input terminal of the amplifier and the second supply terminal, and the parallel combination of the collector-to-emitter path of a second transistor and a voltage divider coupled between the resistor and the rectifying junction. The base of the second transistor is coupled to an intermediate tap of the voltage divider. As the temperature of the circuit increases, the gm of the amplifying transistor decreases. The biasing circuit conducts an increasing amount of current to the amplifier as the operating temperature of the circuit increases. This increase in biasing current causes an increase in the collector current of the amplifying transistor, which stabilizes the gm and hence the gain of the amplifier. |
