| 摘要 |
PURPOSE:To suppress rush current immediately after current supply to a heat emitting resistor by furnishing a base current suppressing means, which gradually increase the base current of a transistor to a certain value. CONSTITUTION:When a heat emitting resistor is being driven, an actuate signal is impressed to the base of No.2 transistor Q2, which is thus turned on. This actuates a base current suppressing means 15 to restrict the base current of No.1 transistor Q1. Therefore, the emitter-collector current of the No.1 transistor Q1 will not flow abruptly, but increase gradually to attain a certain value. This increases also gradually the drive current to the heat emitting resistor in series connection to the emitter/collector of the No.1 transistor Q1. This allows flowing of only small current when the resistance value of the heat emitting resistor itself is small immediately after current supply, which should suppress possible rush current. |
