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Low Avalanche Breakdown Hypothesis

Words and pictures by Robert Garner (June 2007)

For more recent work, see "Weird Parts".

A couple weeks ago I measured the two bad transistors on the Tek curve tracer in the lab. Below are the traces.

One clearly shows a much-lower-than-normal avalanche breakdown voltage of the collector-base junction.

I've scanned 3 pages from my Motorola "High-speed Switching Transistor Handbook" which describes how a transistor latches up if its load line is within the avalanche breakdown region--which could be happening with this down-shifted transistor.

Robert added later:

"I also looked at other 2n130x's and their avalanche breakdowns are way higher.

"The fact that one of the transistors was quite a bit worse is the smoking gun..."

see WeirdParts

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