Above: 90s Honda ignition

• Above: A typical arrangement of an 1980s igniter unit. This device is designed to use the signal from a reluctor type ignition pickup to produce a well controlled output from a power Darlington output transistor.
• "A zener is used at the coil driver collector to limit the voltage and lengthen the spark duration. The circuit should operate reliably with a shorted plug, however operating the circuit with no load connected (plug wires fallen off, etc.) may cause a failure due to most of the power being absorbed by the zener". -B0wd
• Coil Driver: The devices are bipolar Darlington transistors manufactured using Multiepitaxial Planar technology. They have been properly designed to be used in Automotive environment as electronic ignition power actuators. High operating junction temperature. Built in clamping zener.
• ECM: Also known as Engine/Electronic Control Module, Electronic/Engine Control Unit. This is a separate unit that drives mostly the 1990s igniter unit.