Odd Transistor Readings

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Phil Allison 6 years ago

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** You have never revealed the transistor's number.

The OP describes it as being a "TO8 in a tin can" which makes no sense.

A CRO sweep amplifier is not a small signal circuit, it is large signal.

Maybe you meant a TO5 round metal pak like this ?

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Rated at 75V, 2A, 50MHz and 10 watts

The case would glow in the dark at 10 watts.

FYI:

I've seen hundreds like the above with shorted C-E - due to over current, over voltage or over temp.

Ones with low C-E resistance got lucky and were just cooked a bit.

Doped silicon is wacky stuff.

Few texts describe all or even any the failure modes.

..... Phil

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Cursitor Doom 6 years ago

** You have never revealed the transistor's number.

The OP describes it as being a "TO8 in a tin can" which makes no sense.

A CRO sweep amplifier is not a small signal circuit, it is large signal.

Maybe you meant a TO5 round metal pak like this ?

formatting link

Rated at 75V, 2A, 50MHz and 10 watts

The case would glow in the dark at 10 watts.

Probably. Did I write TO-8? I meant to type TO-18. It's a 2N3251 and in this circuit it's working well within its V&A ratings, as one would expect with a design by Hewlett-Packard.

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Phil Allison 6 years ago

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** Pathetic. The max ratings of any BJT on a BJC can be massively exceeded by the simplest of accidents while servicing or even cleaning.

Dropping a toll or screw will do it.

FFS get real.

.... Phil

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Cursitor Doom 6 years ago

** Pathetic. The max ratings of any BJT on a BJC can be massively exceeded by the simplest of accidents while servicing or even cleaning.

Dropping a toll or screw will do it.

FFS get real.

I can't see HTH that's going to happen just out of the blue inside the sealed casing. THE FAULT AROSE *BEFORE* THE CASE WAS EVEN REMOVED.

Anyway, I can see your old attitude problem resurfacing and you reverting to being your usual snarky bastard self so this thread is over AFAIC. I will not be looking for any more replies from you via GG as you're not adding anything of value any more. Have a nice life and enjoy the Rugby World Cup Final Hahaha! >:-}

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Phil Allison 6 years ago

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** Insane.

The scope is decades old, anything could have happened in the past.

Metal case transistors are highly vulnerable cos the collector is exposed.

** Good idea - cos you are raving like a lunatic.

** Listen you ASD f***ed moron -

YOU have the bad attitude.

Big time.

..... Phil

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John-Del 6 years ago

Phil, you've been run out of every group you to which you've ever belonged anywhere in the civilized world.

Yet it never occurs to you that the problem might be *you*...

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