| 摘要 |
PURPOSE:To prevent oscillation of constant electric current by working current- limiting transistors for controlling the base current for a power transistor in the active area within the current limiting section of the current limiting type non-contact ignition equipment. CONSTITUTION:When alternating current signal Vp from an electromagnetic pick-up coil 4 turns from positive to negative, output from a control circuit part 5 becomes large, turning off a transistor 19 and turning on a power transistor 22. Then, voltage decline at the primary current detecting resistor 15 steps up, and when declining voltage at a resister 12 in the standard voltage circuit (8, 11, 12, 17, 18) and the resister 15 becomes almost equal, the transistor 20 is turned off and a transistor 21 is turned on. Due to this, the transistor 21 draws the base current of the power transistor 22, thereby putting current limiting function into full play, but if the drawing of base current goes too far, power decline portion at the resister 15 diminishes, thereby turning on the transistor 20. At this time, however, the current flowing through the resister 16 also flows through the base for transistor 21, resulting in avoidance of switching actions on the part of the transistor 21.
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