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BJTs being phased out?
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David Hess:

--- Quote from: NiHaoMike on October 13, 2020, 11:12:56 pm ---There was a device called the "ESBT" (Emitter Switched Bipolar Transistor) many years back, it's literally just a high voltage bipolar transistor with a low voltage MOSFET in series with the emitter.
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Some high performance switching designs still do that when an IGBT is not fast enough.


--- Quote ---
--- Quote from: David Hess on October 13, 2020, 08:14:52 pm ---- Bipolar transistors have a higher current density than FETs, which leads to less area (cost) for a given current.
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MOSFETs that can switch on the order of 100A are not that uncommon (they're found on every modern motherboard), but a 100A bipolar is pretty exotic.
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IGBTs take advantage of the same thing; have you ever seen a 100 amp IGBT?  Where this matters is at high voltages where MOSFET die size becomes huge.
eti:
Pendant hour is it? These point by point, pick-apart multi-quoting reply posts truly smack of "no no no, no matter what you say, I'm going to pick apart, analyse and refute absolutely everything you've said, wait and see, and I WILL be right!"

Being right is hugely overrated, and also a great waste of one's time. It makes me think many people have naff all better to do than "prove" their (supposed) ability to know more than the other man.

Lighten up - it's not that important in the overall scheme of life, and will you recall who "won" on a forum conversation, when you're in the final hours of your life?

I also sense a disproportionate dose of confirmation bias is present in a lot of these types of threads, and I don't just mean EEVblog, this bullshit is epidemic net-wide from people who can't accept they're not THAT clever all the time, are only human and make mistakes and miscalculations like everyone else.

Calm down, get off your chairs and go for a walk.
coppice:

--- Quote from: tooki on October 15, 2020, 11:04:39 pm ---It seems my hunch was right: while reading up on electrets to try and answer NANDblog’s question, I came across a statement from Shure (one of the big names in pro audio mikes) claiming that “probably 95% of the condenser microphones on the market are the electret type”.

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Interesting. The fairly modern mics I've seen schematics for, or seen inside, had pumps to push the 48V phantom power up to a high voltage. Electrets have real benefits. They can create a really big bias voltage. I had a pair of Pioneer electret headphones in the early 70s. Condenser headphones, like the Stax models, could produce wonderful sound, but struggled to reach high volumes, because they didn't want an extreme bias voltage running down the cable. No problem with the Pioneer electret headphones. They would reach pain levels while maintaining high fidelity.
NiHaoMike:

--- Quote from: David Hess on October 16, 2020, 01:36:32 am ---Some high performance switching designs still do that when an IGBT is not fast enough.

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Isn't that the realm of SiC and GaN transistors nowadays?

--- Quote ---IGBTs take advantage of the same thing; have you ever seen a 100 amp IGBT?  Where this matters is at high voltages where MOSFET die size becomes huge.

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Actually have a few of those in an assembly on the bench. Rated for quite a bit more than 100A, I got it instead of something closer to the 50A or so I actually need for my application because it's cheap.
schmitt trigger:
Indeed, the 2N2646 UJT, being in a metal can is expensive and essentially in the brink of extinction.
But the 2N4870/1 in a plastic TO92 package is significantly cheaper.

PUTs like the 2N6027/8 are another nifty device, although more closely related to thyristors than transistors.

Neither is, or will become, a mainstream device anymore.
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