| 摘要 |
A circuit arrangement is described which provides an approximately constant current despite a fluctuating supply voltage. A first bipolar transistor having it's base-emitter path connected in series with a parallel combination of the base-emitter path of a second bipolar transistor and a second resistor. The collector voltage of the second bipolar transistor controls a third bipolar transistor as a bypass to the base-emitter path of the first bipolar transistor and opposes variation of the base-emitter voltage of the first bipolar transistor. If, for example, the base-emitter voltage of the first bipolar transistor increases as a result of a higher supply voltage, the collector current of the third bipolar transistor is increased and thus the increase in the base current of the first bipolar transistor is reduced, thereby causing negative feedback.
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