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Old 11-04-2016, 04:24 PM
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Joystick TX
 
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Originally Posted by bcchi
O- Boy.Learn something new every day.There is no open and closed circuit in the operation of the Hall sensor.You can call it that if you want.Sounds good ,but not correct.
Static timing should still be set at 28 to 30 degrees BTDC.
BCCHI. Tired old CH guy.
I think kmeyers is referring to the "electronic circuit" inside the Hall Sensor Integrated Circuit. It DOES have an on and off circuit. The Transistor acts as a switch and it is switched ON or OFF by the hall sensor and electronics, which provides a HI to Low voltage, or a Low to HI output signal to the ignition module. The Schmidt Trigger in the IC provides a fast voltage transition, or "edge" from Low to Hi or Hi to Low instead of the "slope" that would be provided without it. A sloping voltage would cause erratic timing. I don't think that would be noticeable in our engines, but in high speed digital applications, it could cause problems. The ignition module can be designed to use either the Hi to Low, or Low to Hi voltage transition as it's "trigger point" then add the appropriate time (advance or delay from TDC) to fire the spark plug.

A Hall Sensor block diagram is attached. The actual one used by DLE may be different, but the function would be the same.

The ignition module can also be designed to use both transitions to calculate the "dwell" time in order to prevent the engine from getting a spark unless the RPM is above a certain RPM. Some engines require this for safety purposes, like on lawn mowers, to inhibit spark below a set RPM, like 400.
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Last edited by Joystick TX; 11-04-2016 at 05:00 PM.