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328P sleep current wildly different between two copies
Speaking of picking things up from Digikey, they sell quite a variety of current sensor ICs with shunt resistance in the milli (and micro I think!) ohm range.  Might take a...
Sunday, 26 July 2020 - 01:17
Requesting advice: MOSFET or IGBT in place of BJT?
Krupski wrote: It's no fun to watch $60 swirl down the drain because some idiot (me) stuck a toe outside the SOA...    Oh, it may be no fun for you, but it's great fun...
Saturday, 25 July 2020 - 03:44
Requesting advice: MOSFET or IGBT in place of BJT?
ki0bk wrote: Use an MJ11033 if you need more current. Jim   They have "interesting" Safe Operating Area curves too.  Ask Me How I Know...    S.
Friday, 24 July 2020 - 03:20
Power BJT strange functioning - am I doing something wrong?
There has also been a LOT of development work in BJTs since the heyday of the 2N3055, but as the graphs show, it has been towards high currents at low voltages.  Your other...
Thursday, 23 July 2020 - 21:31
Power BJT strange functioning - am I doing something wrong?
ron_sutherland wrote: From memory (>20 years ago, so probably wrong), I seem to recall something about current crowding is a problem with large BJT. Once an area of the silicon...
Thursday, 23 July 2020 - 21:16
Power BJT strange functioning - am I doing something wrong?
Just for grinsies  , I had a go at this - making LINEAR graphs of Safe Operating Area for your BUT30V and your 2N3055.  I think this makes clear why your super-duper new...
Thursday, 23 July 2020 - 20:24
Power BJT strange functioning - am I doing something wrong?
Krupski wrote: mikech wrote:Looking at the "Safe Operating Areas" chart 20V at 7A is outside the DC region. That '250W' rating is an "Absolute Maximum Rating"   I think you...
Thursday, 23 July 2020 - 19:02
Sometimes the problem is in the breadboard
The thing about electric transmissions is that the gear ratio is nearly infinite, and the losses very low.  If you want your wheels to turn at 20 rpm and your turbine spins...
Monday, 20 July 2020 - 20:08
Sometimes the problem is in the breadboard
That was barnacle, not me.  Show Nested Quotes indeed!    S.   PS - Incidentally, I think turbines are excellent candidates for electric transmissions. ...
Monday, 20 July 2020 - 15:42
Sometimes the problem is in the breadboard
barnacle wrote: Quote: So which wire do we cut to defuse the bomb, again?  Duh. The *red* one, obviously... Neil   https://www.smbc-comics.com/comi...   Posted...
Monday, 20 July 2020 - 14:30
Sometimes the problem is in the breadboard
The idea was to replace exactly the air turbines in dental drills, which do kick around at that sort of speeds.  Can be done - question is, can you do so economically? ...
Monday, 20 July 2020 - 04:43
Sometimes the problem is in the breadboard
The idea of the silver wire was losses.  This was a little motor that would be rated for 100krpm (Yeah, 100,000 rpm) and not only is silver a better conductor, it had better...
Monday, 20 July 2020 - 02:48

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