MOSFET in avalanche

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Can expert please explain or point to thread which explains this topic as it relates to pi tx circuitry.

[bbsailor]

Can expert please explain or point to thread which explains this topic as it relates to pi tx circuitry.

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MOSFETS have a rated voltage such as 400V. If a flyback spike is 800V the discharge spike will flat top at 400V and not start decaying until the spike falls below 400V. This will extend the delay time, increase the MOSFET heat absorption, raise the MOSFET R-on resistance slightly due to the increased heat and not efficiently charge smaller low TC targets as efficiently as a quick vertical coil discharge. The rule of thumb is that the coil discharge TC should be 5 times faster than the target TC to fully stimulate it. As you can see, this is a balancing act where you have some control over the variables that can be optimized for a specific range of target sizes and types, coil sizes, and TX current.

I hope this helps?

Joseph J. Rogowski