Breaker Point Diagnostics Practice Test

Dwell is the angular span of camshaft rotation during which the ignition points stay closed and the coil is charging. Expressing it in degrees of camshaft rotation ties directly to the mechanical timing controlled by the cam lobes, so it stays consistent as engine speed changes. If you used seconds, RPM, or volts, you’d lose that direct link to the timing interval: seconds convert to different durations at different speeds, RPM is just speed, and volts measure electrical potential, not how long the points stay closed. So the unit that best describes dwell is degrees of camshaft rotation.