Blowing Transistor on Igntion Module

Discussion in 'General Electronics Chat' started by boxchevyman, Jun 3, 2015.

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  1. boxchevyman

    Thread Starter New Member

    Jun 3, 2015
    Hello all!

    First and foremost I’m not very savvy when it comes to circuitry but I have scrounged this site for a while and thought you guys could possibly help me out.

    I am building a CDI triggering mechanism that should collapse the ignition coil when the points open up. That’s the idea anyways; I got plans from this web site: I attempted to make Figure 1

    So I went ahead and made this, and it works for a little while then blows the transistor. I put a new transistor on then it will work for half a minute just to blow again. I’m not sure the cause of this as my base voltage has a resistor on it.

    I’m in over my head but do you guys see any obvious reason why this would happen?

    Thanks for your time,


    Here is a link what i have made, i cant figure out hot to post a picture:
  2. crutschow


    Mar 14, 2008
    The module heat sink ground must be directly connected to the transistor emitter ground. Is it?

    You might try posting your problem here also
  3. boxchevyman

    Thread Starter New Member

    Jun 3, 2015
    Hello, thanks for getting back with me. The wires leading from the heat sink and the transistor are grounded to the same point on the engine. Is that good enough?

    I will also try posting in the forum you mentioned.

    Thanks again,
  4. SgtWookie


    Jul 17, 2007
    Interesting - however, I'm afraid this falls under the topic of "Automotive Modifications", discussion of which is expressly prohibited by the Terms of Service paragraph 6:
    which states:
    When a Moderator sees this thread, it will be closed.
    Sorry, that's the rules established by the site's owners.
  5. Wendy


    Mar 24, 2008
    The owners of All About Circuits have elected not to host discussions of automotive electrical system modifications/enhancements due to safety concerns, the potential of legal ramifications and the possible circumvention of vehicle regulations at the state and federal level.

    This thread is against the AAC forum rules, Chapter 6, as seen here:

    6. Restricted topics. The following topics are regularly raised and however are considered “off-topic” at all times and will results in Your thread being closed without question:

    • Any kind of over-unity devices and systems
    • Automotive modifications
    • Devices designed to electrocute or shock another person
    • LEDs to mains
    • Phone jammers
    • Rail guns and high-energy projectile devices
    • Transformer-less power supplies
    This can be found in our Terms of Service (ToS)

    Automotive modifications of any kind are strictly forbidden. Therefore, this thread will be closed.

    Please try to understand the reasons behind this action, and feel free to browse and use the forums.

    You might find answers to your questions in one of these forums:

    Another good forum that shares many of the same membership is . Good luck.
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