| 摘要 |
PURPOSE:To attain the application of a Zener diode of small capacity by connecting a transistor between the positive and negative lines of a DC power supply and then the Zener diode to the base of the transistor respectively. CONSTITUTION:The collector (c) and the emitter (e) of a transistor TR5 are connected between the lines at the positive and negative sides 2A and 2B of a DC power supply 2 which supplies the electric power to an electronic circuit 1. While the base (b) of the TR5 is connected to the positive line via a Zener diode 4. Thus the greater part of current flows via the TR5 when the voltage of the power supply 2 has fluctuation and the voltage of the positive side line is set sat a high level. At the same time, a small current flows to the energized diode 4 via the base (b) in response to the amplification factor of the TR5. As a result, a Zener diode of small capacity is available to prevent the rise of the supplied voltage caused by the fluctuation of the power supply voltage.
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