Thank you all for viewing my posting,
My intent is to create a revolution limiter for a high energy ignition to see if what I "thought" would work in theory actually works in a functional circuit. In testing my circuit (as shown in the provided schematic) on a distributor testing machine I found the following:
1) With no circuit used, I connected a wire to the coil -/ tach out connector on the cap and touched this to ground with the distributor spinning which shorted to ground and allowing the coil to not have output.
2) I next added the provided circuit which coming from my proven microcontroller circuit SHOULD ground the coil when I press a button/switch.
3) When I tried my circuit as described above I found that whether or not the distributor was spinning, I had no spark whether or not I was pressing the button which told me that the coil was being grounded by my circuit.(if the coil was not grounded the distributor machine would show a spark occurring) and the darlington transistor bu941zt became extremely hot.
4) I added different resistance values(100, 10k, 22k ohms) individually at point -A- to limit current to the darlington but found the circuit to NEVER unground the coil and the distributor worked as if the circuit wasn't even there.
Questions:
1) Can someone point out to me why this circuit is not functioning as I had envisioned?
2) Is there an easier or better way of doing this circuit?
Thank you for helping me understand my errors and making this circuit work.
Peaches
My intent is to create a revolution limiter for a high energy ignition to see if what I "thought" would work in theory actually works in a functional circuit. In testing my circuit (as shown in the provided schematic) on a distributor testing machine I found the following:
1) With no circuit used, I connected a wire to the coil -/ tach out connector on the cap and touched this to ground with the distributor spinning which shorted to ground and allowing the coil to not have output.
2) I next added the provided circuit which coming from my proven microcontroller circuit SHOULD ground the coil when I press a button/switch.
3) When I tried my circuit as described above I found that whether or not the distributor was spinning, I had no spark whether or not I was pressing the button which told me that the coil was being grounded by my circuit.(if the coil was not grounded the distributor machine would show a spark occurring) and the darlington transistor bu941zt became extremely hot.
4) I added different resistance values(100, 10k, 22k ohms) individually at point -A- to limit current to the darlington but found the circuit to NEVER unground the coil and the distributor worked as if the circuit wasn't even there.
Questions:
1) Can someone point out to me why this circuit is not functioning as I had envisioned?
2) Is there an easier or better way of doing this circuit?
Thank you for helping me understand my errors and making this circuit work.
Peaches