| 摘要 |
PURPOSE:To make rising up of power source quick without lowering ripple reduction rate by adding a transistor for speeding up in parallel to resistance of a low-pass filter. CONSTITUTION:A transistor Q3 of NPN type for speeding up is added in parallel to the resistance R of a low-pass filter 5 of a constant voltage source circuit having a ripple filter and the value of the resistance R is determined in relation to the operation of the transistor Q3. That is, the collector of the transistor Q3 is connected to a Vcc voltage source, and the part between the base and emitter is connected to a resistance R and emitter follower connected. The value of the resistance R is set not to make the transistor Q3 on state at the time of normal operation, in other words, to make the product of base current IB2 of a transistor Q2 and the value of resistance R (IB2.R) sufficiently smaller than voltage VBE3 between the base and emitter of the transistor Q3 for speeding up.
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