| 摘要 |
To improve an ignition system as described in U.S. Pat. No. 4,176,645, Jundt et al., in which a threshold switch is provided which controls current flow through the ignition coil, the turn-ON point of the current flow being determined, in part, by an integrator, and to prevent malfunction due to corroded terminals, improper installation and the like, a variable resistance branch, including a transistor 66, is connected across the integrator 31, 44, and so connected that, as the supply voltage drops, the effect of the integrator 31, 44 on the threshold switch 15, 16 is decreased, thus preventing modification of the inherent threshold level of the threshold switch by the action of the integrator. The transistor 66 in the variable resistance circuit 64 may be connected as a comparator, having its base connected to a junction J at fixed voltage (Zener diode 68, resistor 69), which is compared with the emitter-collector voltage, connected across the integrator 31, 44, and simultaneously changing its resistance value as the comparison is effected.
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