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Gentlemen,
I guess this is going to be a non-starter, but here goes:
Can I put two BT137 8 Amp triacs in parallel and get a 16 Amp
capability from them?
Gentlemen,
I guess this is going to be a non-starter, but here goes:
Can I put two BT137 8 Amp triacs in parallel and get a 16 Amp
capability from them?
CD
On Mon, 08 May 2023 19:35:43 +0100, Cursitor Doom <cd@notformail.com
wrote:
Gentlemen,
I guess this is going to be a non-starter, but here goes:
Can I put two BT137 8 Amp triacs in parallel and get a 16 Amp
capability from them?
CD
Probably, but you could try it. Make sure both have hard gate drives
and a common heat sink.
At high currents, they will become more ohmic with positive TCs so
should share reasonably well. The zero-TC current should show up on
the data sheet.
Big potted power diodes are often a bunch of little diodes in
parallel.
On Mon, 08 May 2023 12:18:12 -0700, John Larkin
jlarkin@highlandSNIPMEtechnology.com> wrote:
On Mon, 08 May 2023 19:35:43 +0100, Cursitor Doom <cd@notformail.com
wrote:
Gentlemen,
I guess this is going to be a non-starter, but here goes:
Can I put two BT137 8 Amp triacs in parallel and get a 16 Amp
capability from them?
CD
Probably, but you could try it. Make sure both have hard gate drives
and a common heat sink.
At high currents, they will become more ohmic with positive TCs so
should share reasonably well. The zero-TC current should show up on
the data sheet.
Big potted power diodes are often a bunch of little diodes in
parallel.
One assumes they\'re all matched for barrier height profile, though.
And set so close together for minimum temperature difference?
I\'ll give it a go; got nothing to lose after all.
On Mon, 08 May 2023 21:49:17 +0100, Cursitor Doom <cd@notformail.com
wrote:
On Mon, 08 May 2023 12:18:12 -0700, John Larkin
jlarkin@highlandSNIPMEtechnology.com> wrote:
On Mon, 08 May 2023 19:35:43 +0100, Cursitor Doom <cd@notformail.com
wrote:
Gentlemen,
I guess this is going to be a non-starter, but here goes:
Can I put two BT137 8 Amp triacs in parallel and get a 16 Amp
capability from them?
CD
Probably, but you could try it. Make sure both have hard gate drives
and a common heat sink.
At high currents, they will become more ohmic with positive TCs so
should share reasonably well. The zero-TC current should show up on
the data sheet.
Big potted power diodes are often a bunch of little diodes in
parallel.
One assumes they\'re all matched for barrier height profile, though.
Buy identical parts, of course.
We\'ve made deals with distibutors to buy 20 parts off a reel so we can
test them, and then buy the rest of that exact reel.
And set so close together for minimum temperature difference?
I\'ll give it a go; got nothing to lose after all.
Measure their voltage drops or temperatures to estimate sharing.
On Mon, 08 May 2023 14:08:39 -0700, John Larkin
jlarkin@highlandSNIPMEtechnology.com> wrote:
On Mon, 08 May 2023 21:49:17 +0100, Cursitor Doom <cd@notformail.com
wrote:
On Mon, 08 May 2023 12:18:12 -0700, John Larkin
jlarkin@highlandSNIPMEtechnology.com> wrote:
On Mon, 08 May 2023 19:35:43 +0100, Cursitor Doom <cd@notformail.com
wrote:
Gentlemen,
I guess this is going to be a non-starter, but here goes:
Can I put two BT137 8 Amp triacs in parallel and get a 16 Amp
capability from them?
CD
Probably, but you could try it. Make sure both have hard gate drives
and a common heat sink.
At high currents, they will become more ohmic with positive TCs so
should share reasonably well. The zero-TC current should show up on
the data sheet.
Big potted power diodes are often a bunch of little diodes in
parallel.
One assumes they\'re all matched for barrier height profile, though.
Buy identical parts, of course.
We\'ve made deals with distibutors to buy 20 parts off a reel so we can
test them, and then buy the rest of that exact reel.
And set so close together for minimum temperature difference?
I\'ll give it a go; got nothing to lose after all.
Measure their voltage drops or temperatures to estimate sharing.
Okay..... but these aren\'t adjustable characteristics, so what do I do
with the resuts?
On Mon, 08 May 2023 23:08:03 +0100, Cursitor Doom <cd@notformail.com
wrote:
On Mon, 08 May 2023 14:08:39 -0700, John Larkin
jlarkin@highlandSNIPMEtechnology.com> wrote:
On Mon, 08 May 2023 21:49:17 +0100, Cursitor Doom <cd@notformail.com
wrote:
On Mon, 08 May 2023 12:18:12 -0700, John Larkin
jlarkin@highlandSNIPMEtechnology.com> wrote:
On Mon, 08 May 2023 19:35:43 +0100, Cursitor Doom <cd@notformail.com
wrote:
Gentlemen,
I guess this is going to be a non-starter, but here goes:
Can I put two BT137 8 Amp triacs in parallel and get a 16 Amp
capability from them?
CD
Probably, but you could try it. Make sure both have hard gate drives
and a common heat sink.
At high currents, they will become more ohmic with positive TCs so
should share reasonably well. The zero-TC current should show up on
the data sheet.
Big potted power diodes are often a bunch of little diodes in
parallel.
One assumes they\'re all matched for barrier height profile, though.
Buy identical parts, of course.
We\'ve made deals with distibutors to buy 20 parts off a reel so we can
test them, and then buy the rest of that exact reel.
And set so close together for minimum temperature difference?
I\'ll give it a go; got nothing to lose after all.
Measure their voltage drops or temperatures to estimate sharing.
Okay..... but these aren\'t adjustable characteristics, so what do I do
with the resuts?
See if it works.
On Monday, May 8, 2023 at 2:38:14?PM UTC-4, Cursitor Doom wrote:
Gentlemen,
I guess this is going to be a non-starter, but here goes:
Can I put two BT137 8 Amp triacs in parallel and get a 16 Amp
capability from them?
Triacs are like SCRs, in that when the current drops close to zero, they cut off. You might need to do something to prevent this. You will also need to do something to balance the current anyway. How will you limit the current to 8 amps in either device? Any irregularity will cause more current to flow in one, than the other.
On Mon, 08 May 2023 19:35:43 +0100, Cursitor Doom <c...@notformail.com
wrote:
Gentlemen,
I guess this is going to be a non-starter, but here goes:
Can I put two BT137 8 Amp triacs in parallel and get a 16 Amp
capability from them?
CD
Probably, but you could try it. Make sure both have hard gate drives
and a common heat sink.
At high currents, they will become more ohmic with positive TCs so
should share reasonably well. The zero-TC current should show up on
the data sheet.
Big potted power diodes are often a bunch of little diodes in
parallel.
On Mon, 08 May 2023 12:18:12 -0700, John Larkin
jla...@highlandSNIPMEtechnology.com> wrote:
On Mon, 08 May 2023 19:35:43 +0100, Cursitor Doom <c...@notformail.com
wrote:
Gentlemen,
I guess this is going to be a non-starter, but here goes:
Can I put two BT137 8 Amp triacs in parallel and get a 16 Amp
capability from them?
CD
Probably, but you could try it. Make sure both have hard gate drives
and a common heat sink.
At high currents, they will become more ohmic with positive TCs so
should share reasonably well. The zero-TC current should show up on
the data sheet.
Big potted power diodes are often a bunch of little diodes in
parallel.
One assumes they\'re all matched for barrier height profile, though.
And set so close together for minimum temperature difference?
I\'ll give it a go; got nothing to lose after all.
On Monday, May 8, 2023 at 4:49:26â¯PM UTC-4, Cursitor Doom wrote:
On Mon, 08 May 2023 12:18:12 -0700, John Larkin
jla...@highlandSNIPMEtechnology.com> wrote:
On Mon, 08 May 2023 19:35:43 +0100, Cursitor Doom <c...@notformail.com
wrote:
Gentlemen,
I guess this is going to be a non-starter, but here goes:
Can I put two BT137 8 Amp triacs in parallel and get a 16 Amp
capability from them?
CD
Probably, but you could try it. Make sure both have hard gate drives
and a common heat sink.
At high currents, they will become more ohmic with positive TCs so
should share reasonably well. The zero-TC current should show up on
the data sheet.
Big potted power diodes are often a bunch of little diodes in
parallel.
One assumes they\'re all matched for barrier height profile, though.
And set so close together for minimum temperature difference?
I\'ll give it a go; got nothing to lose after all.
Even if it passes your test, why would you expect it to continue to pass with parts from different lots or with even small process changes?
Gentlemen,
I guess this is going to be a non-starter, but here goes:
Can I put two BT137 8 Amp triacs in parallel and get a 16 Amp
capability from them?
On Monday, May 8, 2023 at 11:38:14?AM UTC-7, Cursitor Doom wrote:
Gentlemen,
I guess this is going to be a non-starter, but here goes:
Can I put two BT137 8 Amp triacs in parallel and get a 16 Amp
capability from them?
Yeah, with a tiny bit of isolation, that\'ll work. For paralleling diodes
(and preventing current-hog problems) it takes a bit of series inductance for
each diode. That should work for triacs, too (you don\'t get normal triggering
on slower device #2 if device #1 has acheved low-terminal-voltage already,
because triggering is less effective if main terminal voltage drop is low).
On Mon, 8 May 2023 21:25:36 -0700 (PDT), whit3rd <whit3rd@gmail.com
wrote:
On Monday, May 8, 2023 at 11:38:14?AM UTC-7, Cursitor Doom wrote:
Gentlemen,
I guess this is going to be a non-starter, but here goes:
Can I put two BT137 8 Amp triacs in parallel and get a 16 Amp
capability from them?
Yeah, with a tiny bit of isolation, that\'ll work. For paralleling diodes
(and preventing current-hog problems) it takes a bit of series inductance for
each diode. That should work for triacs, too (you don\'t get normal triggering
on slower device #2 if device #1 has acheved low-terminal-voltage already,
because triggering is less effective if main terminal voltage drop is low).
That\'s an interesting idea, using a bit of inductance to limit the
current through each triac to <8A. Damn sight more practical than
power resistors! Well done. I might just use that.
At what frequency?On Tue, 09 May 2023 09:57:37 +0100, Cursitor Doom <c...@notformail.com
wrote:
On Mon, 8 May 2023 21:25:36 -0700 (PDT), whit3rd <whi...@gmail.com
wrote:
On Monday, May 8, 2023 at 11:38:14?AM UTC-7, Cursitor Doom wrote:
Gentlemen,
I guess this is going to be a non-starter, but here goes:
Can I put two BT137 8 Amp triacs in parallel and get a 16 Amp
capability from them?
Yeah, with a tiny bit of isolation, that\'ll work. For paralleling diodes
(and preventing current-hog problems) it takes a bit of series inductance for
each diode. That should work for triacs, too (you don\'t get normal triggering
on slower device #2 if device #1 has acheved low-terminal-voltage already,
because triggering is less effective if main terminal voltage drop is low).
That\'s an interesting idea, using a bit of inductance to limit the
current through each triac to <8A. Damn sight more practical than
power resistors! Well done. I might just use that.
How many henries?
On Tuesday, May 9, 2023 at 6:29:11?AM UTC-7, John Larkin wrote:
On Tue, 09 May 2023 09:57:37 +0100, Cursitor Doom <c...@notformail.com
wrote:
On Mon, 8 May 2023 21:25:36 -0700 (PDT), whit3rd <whi...@gmail.com
wrote:
On Monday, May 8, 2023 at 11:38:14?AM UTC-7, Cursitor Doom wrote:
Gentlemen,
I guess this is going to be a non-starter, but here goes:
Can I put two BT137 8 Amp triacs in parallel and get a 16 Amp
capability from them?
Yeah, with a tiny bit of isolation, that\'ll work. For paralleling diodes
(and preventing current-hog problems) it takes a bit of series inductance for
each diode. That should work for triacs, too (you don\'t get normal triggering
on slower device #2 if device #1 has acheved low-terminal-voltage already,
because triggering is less effective if main terminal voltage drop is low).
That\'s an interesting idea, using a bit of inductance to limit the
current through each triac to <8A. Damn sight more practical than
power resistors! Well done. I might just use that.
How many henries?
At what frequency?
On Tue, 9 May 2023 08:10:05 -0700 (PDT), Ed Lee
edward.ming.lee@gmail.com> wrote:
On Tuesday, May 9, 2023 at 6:29:11?AM UTC-7, John Larkin wrote:
On Tue, 09 May 2023 09:57:37 +0100, Cursitor Doom <c...@notformail.com
wrote:
On Mon, 8 May 2023 21:25:36 -0700 (PDT), whit3rd <whi...@gmail.com
wrote:
On Monday, May 8, 2023 at 11:38:14?AM UTC-7, Cursitor Doom wrote:
Gentlemen,
I guess this is going to be a non-starter, but here goes:
Can I put two BT137 8 Amp triacs in parallel and get a 16 Amp
capability from them?
Yeah, with a tiny bit of isolation, that\'ll work. For paralleling diodes
(and preventing current-hog problems) it takes a bit of series inductance for
each diode. That should work for triacs, too (you don\'t get normal triggering
on slower device #2 if device #1 has acheved low-terminal-voltage already,
because triggering is less effective if main terminal voltage drop is low).
That\'s an interesting idea, using a bit of inductance to limit the
current through each triac to <8A. Damn sight more practical than
power resistors! Well done. I might just use that.
How many henries?
At what frequency?
Oh dear. I haven\'t done the sums yet and I have a feeling it\'s going
to end up implausibly huge.
On Tue, 09 May 2023 16:38:58 +0100, Cursitor Doom <cd@notformail.com
wrote:
On Tue, 9 May 2023 08:10:05 -0700 (PDT), Ed Lee
edward.ming.lee@gmail.com> wrote:
On Tuesday, May 9, 2023 at 6:29:11?AM UTC-7, John Larkin wrote:
On Tue, 09 May 2023 09:57:37 +0100, Cursitor Doom <c...@notformail.com
wrote:
On Mon, 8 May 2023 21:25:36 -0700 (PDT), whit3rd <whi...@gmail.com
wrote:
On Monday, May 8, 2023 at 11:38:14?AM UTC-7, Cursitor Doom wrote:
Gentlemen,
I guess this is going to be a non-starter, but here goes:
Can I put two BT137 8 Amp triacs in parallel and get a 16 Amp
capability from them?
Yeah, with a tiny bit of isolation, that\'ll work. For paralleling diodes
(and preventing current-hog problems) it takes a bit of series inductance for
each diode. That should work for triacs, too (you don\'t get normal triggering
on slower device #2 if device #1 has acheved low-terminal-voltage already,
because triggering is less effective if main terminal voltage drop is low).
That\'s an interesting idea, using a bit of inductance to limit the
current through each triac to <8A. Damn sight more practical than
power resistors! Well done. I might just use that.
How many henries?
At what frequency?
Oh dear. I haven\'t done the sums yet and I have a feeling it\'s going
to end up implausibly huge.
Or infinite if there is any DC component in the current.
On Tuesday, May 9, 2023 at 6:29:11â¯AM UTC-7, John Larkin wrote:
On Tue, 09 May 2023 09:57:37 +0100, Cursitor Doom <c...@notformail.com
wrote:
On Mon, 8 May 2023 21:25:36 -0700 (PDT), whit3rd <whi...@gmail.com
wrote:
... For paralleling diodes
(and preventing current-hog problems) it takes a bit of series inductance for
each diode. That should work for triacs, too (you don\'t get normal triggering
on slower device #2 if device #1 has acheved low-terminal-voltage already,
because triggering is less effective if main terminal voltage drop is low).
That\'s an interesting idea, using a bit of inductance to limit the
current through each triac to <8A. Damn sight more practical than
power resistors! Well done. I might just use that.
How many henries?
At what frequency?