A secondary ignition waveform is not just about the coil; it is also about the resistance of the air and fuel mixture inside the combustion chamber. When you are looking at a secondary ignition waveform, you need to be looking at the spikes and the hash in between. Measuring the voltage of the secondary ignition directly is not an option. The high voltages will damage any scope or meter. Capturing a secondary ignition waveform requires a capacitive probe. This type of probe can be either the traditional clamp over an ignition wire or a “paddle” that makes contact with the surface of the coil or wire.