Re: How do Atom Computer Ignition modules work?

[legendre]

quote debe:

Hi lgendre, no the MJE13007A wont work because its not a Darlington type transistor so its gain (hfe) is too low. Ive tried a lot of transistors & failed until I found & tried 2SD1071. They are cheep I purchased 10 of them for $12.87 + $4.95 freight on Ebay from China. I suspect the Atom module used a custom made darlington transistor as it just had (atom A1) on it.

Oh, doh!

Right, right you are sir.. for some reason I was thinking the 13007 was a Darlington device. In fact, it’s a rather low-gain device that’s better suited to switching supplies and small-scale CRT horizontal output service. It’s a great general-purpose part for repairing the horiz. sweep circuits in numerous B&W / monochrome CRT displays, though.

I saw that ‘ATOM’ marking on the transistor.. not sure what to think. It’s a lot easier to have a batch of an off-the-shelf part run with your own markings, than to design & produce a proprietary transistor. Then again, who knows – we’d have to grab the ear of one of the Atom engineers!

FYI – for you geek types out there.. there are some pretty hard-core, high-voltage / current transistors to be salvaged from the "100W equivalent" CFL lamps. They use a part that’s very much along the lines of the mentioned MJE13007A – but I can’t attest to the topology (Darlington vs. conventional). You’ll also find a couple of high-voltage 105C caps inside those things as well.