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Absolutely, positively, stunning! John

How about a hybrid taking the best of both designs? In other words, add my protections to your circuit and call it a day. OK, so my circuit takes much less power. Does that even matter if we have to supply juice to the halls? In addition, I have a diode drop in the gate drive to the IGBT...

Thanks for the advice. I reduced the values of the current limiting resistors to account for the additional drop introduced by the 100 ohm series resistor on the output of the hall. It's only there to avoid "spiking" the hall if there is a breakdown somewhere else in the circuit. So, the 270...

No worries Bill! I love that ancient proverb. I will remember that one! The book "Ignition Coils and Magnetos in Miniature" by the late Bob Shores is a good source of info. The book is still available from Mrs. Shores at a very reasonable price. http://www.bobshores.com/home.html Scroll...

Now that is funny! I was, however, commenting on the engine. The girl never popped up on my screen, so I can't comment Rof} The weird thing is I used to see ads on this site, but now I never see any. The one that annoyed me was a bogus "You've been unfriended by 3 people." John

The circuit is built and working. I needed to increase the value of the AC coupling capacitor to make it easier to test. I am getting a strong spark with no cap across the transistor. This lends a lot of creedence to Mayhugh's explanation since my coil with breaker points gave no spark...

Rich, she looks great! John

Bill, I think Sage's circuit is just that. It's very simple, yet it works and works well. While mine has more protections against power transients and such and lower "standby" power consumption, it is more complicated as a result. All that said, it holds no advantage over Sage's with...

RWO, I been meaning to experiment with that part just for the fun of it. I wasn't aware that was the basis for the GM HEI circuit. I wonder, though, how applicable the reluctor input is to us? On the other hand, the input circuit would be easily adapted to a hall sensor, at least from what...

Terry, I think you've done a terrific job of describing the situation and hit the nail on the head to be sure. That said, I think the dream of a more or less universal ignition coil circuit is nonetheless attainable. However, the coil characteristics and the engine dynamics are indeed...

Rich, I'm glad to hear it all worked out so far. Keep us posted on your life test. Cheers, John

Creast, No need to rewire the coil it should be OK the way it is. dsage's circuit is just fine. My circuit is well on it's way to being completed and I expect to have test results on Monday along with any circuit revisions that were necessary to: 1) Ensure robust operation despite component...

Luc, Remember he said this? (see above) His hall is running from 12V despite what the schematic shows... John

Sage, Thanks for pointing that out. I went back and fixed it. As far as the ignition scope is concerned, I got mine from a coworker for $50 which is what he paid for it at a flea market. It's still in its original box (including the corrugatred overbox) and is in perfect condition. We all...

By the way Creast, what hall sensor are you using? Can you give us the part number? If not, verify you have the correct pin out. Generally they are as follows: pin 1: Power pin 2: Ground pin 3: Out I can't help but wonder if you have output and power pins reversed... The hall will...

Luc, He did give his circuit diagram. It's in his original post... And, bipolar, non-latching, hall sensors are "you've seen one, you've seen them all". My suggestions were for general filtering, bypassing, and transient protection. If you'd draw out my recommendations, you'd see that it is not...

RWO, I'm not so sure yet that we can or cannot draw an analogy to a full size car coil wiuth huge inductances as compared to the small 6 or 12V coils used in model engines. The fact remains that without a cap across the breaker points in my test setup, I get no spark. I've been struggling to...

Again, the capacitor does more than prevent arcing. It provides a bidirection path for the flyback current, thus the circuit is not open... In any case, even if there is no capacitor, the circuit is not floating when the transistor turns off. An ignition coil is an autotransformer and...

Thanks. I've been trying to beg or borrow a high voltage scope probe to make life easier during experimentation so I can use a regular oscilloscope. I have an old CRT type ignition analyzer, but it's big, bulky and has no waveform storage capability so documentation would be nearly...

Jerry, I believe you are mostly correct. However, a diode across the primary clamps the kickback voltage (since it spikes positive by a few hundred volts at the collector of the transistor when it turns off). While this would give a path for the current as you state, but it also affects the...