Laser FWD L4-1997cc 2.0L DOHC Turbo (1993)
Power Transistor: Description and Operation
Ignition Coil And Power Transistor Circuit
Purpose
The power transistor controls ignition current by interrupting the ignition coil primary ground causing secondary circuit discharge.
Location
The power transistor is located on the intake manifold.
Operation
The ECU controls ignition timing through the power transistor. The power transistor is a type of switch that allows a very low voltage (from the
ECU) to control a larger amount of voltage (negative side of coil).
It is actually two power transistors combined into one unit, controlling each circuit of the dual ignition coil. During engine cranking, the ignition
timing is fixed at 5°BTDC.
