| 摘要 |
PURPOSE:To permit the stable control for the electric conduction of a glow plug with the simple constitution by installing a base voltage raising means for permitting the use in the saturation region for a transistor for controlling the supplied electric power of the glow plug, independently of the load variation of the glow plug. CONSTITUTION:When a key switch 12 is connected with an ON terminal 12a, a lamp timer 17, glow timer 18, and an after glow timer 19 start time counting. If the temperature of the cooling water is low, and each L-signal is outputted from the output terminals 16a and 16b of a water temperature judging device 16, the output of an inverter 23 becomes that at L-level, and a glow lamp 22 comes ON. Since the voltage level applied onto the base of a PNP transistor Tr1 becomes L, and the conversion output voltage supplied from a DC-DC converter 21 as voltage raising means is applied onto an emitter, Tr1 is turned ON. Therefore, Tr2 is turned ON by the application of the base voltage onto the NPN transistor Tr2, and a glow plug 14 is allowed to conduct.
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