I missed the missing diode in the nte256! I have received a few
recommendations and am starting to become confused.

If I use the
MJH11017 will I need to add an additional diode to the circuit? If I do,
could someone detail where in the circuit I would add it?

In article <4UfZj.1069$J04.731 at (no spam) fe087.usenetserver.com>,
Gary L. Woodruff <woodruffrepair at (no spam) frontiernet.net> wrote:

I missed the missing diode in the nte256! I have received a few
recommendations and am starting to become confused.

I diagnose "toxic option shock". A cool washcloth on the forehead, a
chilled beer, and 24 hours of not thinking about the problem usually
helps.

There's almost certainly no one "right" or "best" solution for what
you're trying to accomplish... there are many substitutions that you
can make, which will work acceptably.

If I use the
MJH11017 will I need to add an additional diode to the circuit? If I do,
could someone detail where in the circuit I would add it?

If you use a Darlington or IGBT which does not include a reverse
diode, you should add one - otherwise, the transistor may experience a
high-voltage spike when it's switched off (due to the energy stored in
the motor's windings) and this could exceed the Vce(max) and pop the
device.

The diode would be added in parallel with the collector/emitter pins
of the Darlington or IGBT - cathode to collector, anode to emitter.
Just take a look at the internal schematic for the original Darlington
switch, and make your new arrangement look like that electrically.


Dave, I guess this is where my confusion starts. I see diode E -C

Dave, I guess this is where my confusion starts. I see diode E -C
in the http://www.onsemi.com/pub_link/Collateral/MJH11017-D.PDF circuit
diagram. Am I correct that I would NOT need to add a diode to this?

In article <4BjZj.5269$mz3.4560 at (no spam) fe101.usenetserver.com>,
Gary L. Woodruff <woodruffrepair at (no spam) frontiernet.net> wrote:

Dave, I guess this is where my confusion starts. I see diode E -C
in the http://www.onsemi.com/pub_link/Collateral/MJH11017-D.PDF circuit
diagram. Am I correct that I would NOT need to add a diode to this?

I believe you are correct. This family of Darlingtons does include a
reverse diode, and would not need an external one.

HOWEVER: the MJH11017 is a PNP Darlington! If I recall correctly,
the one you're seeking to replace is an NPN Darlington. Not compatible!

You'd want to use an MJH11018, which is the NPN equivalent of the
MJH11017, to replace an existing NPN part.

Dave, Thanks, I did catch that I needed the 11018 for NPN from the data

legg wrote:

Taking a look at my own usual supplier, the closest thing
electrically, and in stock from Digikey, is the MJH11017.


http://search.digikey.com/scripts/DkSearch/dksus.dll?Detail?name=MJH11022GOS-ND

http://www.onsemi.com/pub_link/Collateral/MJH11017-D.PDF

RL
I missed the missing diode in the nte256! I have received a few
recommendations and am starting to become confused. If I use the
MJH11017 will I need to add an additional diode to the circuit? If I do,
could someone detail where in the circuit I would add it?

The MJH11017-d is an electrical equivalent. No extra parts needed.

In article <4BjZj.5269$mz3.4560 at (no spam) fe101.usenetserver.com>,
Gary L. Woodruff <woodruffrepair at (no spam) frontiernet.net> wrote:

Dave, I guess this is where my confusion starts. I see diode E -C
in the http://www.onsemi.com/pub_link/Collateral/MJH11017-D.PDF circuit
diagram. Am I correct that I would NOT need to add a diode to this?

I believe you are correct. This family of Darlingtons does include a
reverse diode, and would not need an external one.

HOWEVER: the MJH11017 is a PNP Darlington! If I recall correctly,
the one you're seeking to replace is an NPN Darlington. Not compatible!

You're right. Boot to the head.

You'd want to use an MJH11018, which is the NPN equivalent of the
MJH11017, to replace an existing NPN part.