| 摘要 |
PURPOSE:To reduce a loss of electric power, by driving a load by a Darlington circuit which is operated as a Darlington transistor in case of a transient operation, and is operated as one transistor in case of a steady operation. CONSTITUTION:When a switch 4 is closed, a base current flows into a transistor 2 through a resistance 1 from a DC electric power source 5. Immediately after the switch 4 has been closed, voltage exceeding several volts is applied between the collector and the emitter (C-E) of the transistor 2, therefore, the base current flows through a resistance 7 to a transistor 6, too. This base current is hPE-multiplied by the transistor 6 and is supplied to the base of the transistor 2, therefore, the transistor 2 is capable of supplying a large load current to a load 3. As a result, voltage between C and E of the transistor 2 decreases as time elapses, the transistor 6 is turned off, and the base current is supplied to the transistor 2, only through the resistance 1. |
