Origionally, they used a voltage generating pickup, like old electronic ignitions. Then they moved to hall sensors triggered from the gap. Lately, yet another option, as a cost saving measure, they use thin magnet rings with alternating N/S poles like brushless electrical motors use. At least those are the ones I am currently familiar with.LeeScrounger said:Interesting to learn about the different sensor types.
What method does the sensor for automotive anti-lock brakes use? It too reads a toothed gear.
Check out this link for hall effect gear sensors.That's not a hall sensor, it's a pickup coil. They are used in diesel engines to check the speed for the governor