| 摘要 |
The generator, usable in telephony, provides an adjustable current with the aid of an external resistor (28). It comprises three branches connected between a supply (+V) and a single internal impedance (10) for closing the circuit. One of the branches includes a diode-configured upstream transistor (12) in series with a downstream transistor (14a, 14b) biased to the energy-band jump voltage, a second branch includes an upstream transistor (16) in series with a diode-configured downstream transistor (22), and a third branch includes an upstream transistor (18) in series with a downstream transistor (22) for duplicating the current passing through the downstream transistor of the second branch, the bases of the upstream transistors (12, 16, 18) are taken to the same potential and the bases of the downstream transistors (20, 22) of the second and third branches are joined to an output for connection of the external adjusting resistor (28), the output current (I) being extracted between the transistors (18, 22) of the third branch. <IMAGE>
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