I dont understand the pulse I am getting out of the magnetic pickup sensor on the ignition system of an engine.
I need to understand exactly what part of the pulse triggers the electronic ignition unit so I can build a circuit that emulates it. I put a scope across the pickup to see what is there. The pickup is ungrounded at about 100ohm across two leads, the two leads from this pickup go into the CDI unit that measures about 3k across the two leads with one lead going to ground.
My first thought was that the CDI uses ground as zero volts and the pickup coil would generate about 1v positive pulse as a trigger .... not so.
The scope trace shows the pulse to be made of a negative slope - a pause - then a positive slope, each of the 3 sections some 500us long.
I checked this input pulse against the output of the CDI to find that it is the negative slope that triggers the spark.
I can build a device that sends a voltage as a trigger but do not have a clue about building one that generates a -2v. HELP please.
I need to understand exactly what part of the pulse triggers the electronic ignition unit so I can build a circuit that emulates it. I put a scope across the pickup to see what is there. The pickup is ungrounded at about 100ohm across two leads, the two leads from this pickup go into the CDI unit that measures about 3k across the two leads with one lead going to ground.
My first thought was that the CDI uses ground as zero volts and the pickup coil would generate about 1v positive pulse as a trigger .... not so.
The scope trace shows the pulse to be made of a negative slope - a pause - then a positive slope, each of the 3 sections some 500us long.
I checked this input pulse against the output of the CDI to find that it is the negative slope that triggers the spark.
I can build a device that sends a voltage as a trigger but do not have a clue about building one that generates a -2v. HELP please.