This Ignition Kill circuit has been giving me a headache for days. This is the umpteenth version and it won't work either, but perhaps someone here will come up an ingenious solution that never would have occurred to the likes of me.
I need to gnd the ignition after a Briggs/Alternator combo has finished charging a battery. Plan A (subject to massive revision based on what I learn here) is a normally closed reed relay. I'll open it initially with the starter circuit. U1A goes up energizing Q8 and I haven't figured the current limiting resistor yet.
The starter circuit gives up when tach output (U1C) goes down. So we switch to Q6 altho I'm not sure that's the proper application for a PNP. Might be wishful thinking on my part .....
Now the motor's running, we're charging. The input at U3A will come from a shunt in the charging wire, get amplified, and applied to U1D. The + input at U1D gets over the 5.6v Zener ref depending on adj at the 10K pot. Output goes up. Energizes Q7, plugs Q6 ... but maybe not ... it's a PNP and I'm not real clear on them! LOL!
As the battery charges and the U3A input drops, U1D will flip shutting off Q7 which will let the relay close and ground the ignition. But unfortunately the motor will still be spinning. That means we'll still have tach output which will pick up where Q7 left off and it'll keep right on running.
Somehow I need to get the ignition on until we're up to speed and charging, without having an affect once it shuts off.
I hope I've explained myself well enough. All thoughts or suggestions are welcome ....
SP
I need to gnd the ignition after a Briggs/Alternator combo has finished charging a battery. Plan A (subject to massive revision based on what I learn here) is a normally closed reed relay. I'll open it initially with the starter circuit. U1A goes up energizing Q8 and I haven't figured the current limiting resistor yet.
The starter circuit gives up when tach output (U1C) goes down. So we switch to Q6 altho I'm not sure that's the proper application for a PNP. Might be wishful thinking on my part .....
Now the motor's running, we're charging. The input at U3A will come from a shunt in the charging wire, get amplified, and applied to U1D. The + input at U1D gets over the 5.6v Zener ref depending on adj at the 10K pot. Output goes up. Energizes Q7, plugs Q6 ... but maybe not ... it's a PNP and I'm not real clear on them! LOL!
As the battery charges and the U3A input drops, U1D will flip shutting off Q7 which will let the relay close and ground the ignition. But unfortunately the motor will still be spinning. That means we'll still have tach output which will pick up where Q7 left off and it'll keep right on running.
Somehow I need to get the ignition on until we're up to speed and charging, without having an affect once it shuts off.
I hope I've explained myself well enough. All thoughts or suggestions are welcome ....
SP
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