Need help locating Transistor or equiv

howdy all,

I am trying to replace a transistor 2SD829. Here is a link to a data sheet.

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I need the replacements asap so common replacement would be great.

any help would be greatly appreciated.

thanks, Gary

Reply to
Gary L. Woodruff
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anything, no one answers the phone or responds to emails. i have started a paypal dispute as I have already paid. Beware of this site.

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Reply to
Gary L. Woodruff

(was: Need help locating Transistor or equiv)

Gary L. Woodruff wrote:

A Web search shows others have been scammed by these crooks.

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Another curious bit of evidence:

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Reply to
JeffM

As this is a somewhat unusual package, I suspect you're going to find it difficult to find a direct drop-in replacement.

Depending on the circuit application, you might be able to substitute a more modern sort of part. It looks as if the 2SD829 is a power Darlington, intended for use as a saturated switch. It might be possible to adapt the circuit to use something like an IGBT, and use a different package which can be mounted on the existing heat-sink.

Take a look at the International Rectifier IGBTs (they're page 992 and

993 in the last-year's Digi-Key catalog I have here).

There appear to be some tradeoffs in the selection. The 250-volt parts in TO-247 packages have Vcd(sat) values similar to those of the

2SD829, and much higher pulse- and continuous-current and power-dissipation ratings, but don't have an internal reverse diode.

The parts that do have an internal reverse diode, and current and power ratings which match or exceed those of the 2SD829, all seem to have a slightly higher Vce(sat)... but as these are at a higher current level, this may not be an issue.

As one possible example: the IRG4PC40 is a 600-volt part, in a TO-247AC package, with Vce(sat) maximum of 1.85 volts, 49-amp continuous current rating at 25 degrees C, pulse current IC(max) of

200 amps, 160-watt maximum power dissipation, and it has an internal reverse diode. You *might* need an external gate-pulldown resistor, or might not, depending in the circuit driving it (and might need a series resistor of a few ohms on the gate to avoid snivets, if the existing bipolar-drive base resistor won't serve). $5.74 in onesies in last year's catalog (the newer ROHS equivalent part IRG4PC40PBF is a couple of bucks more).
--
Dave Platt                                    AE6EO
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Reply to
Dave Platt

Thanks for the info. I only have a small pcb with a few diodes and resistors, a couple of relays, and the transistor. It is a forklift circuit so I believe it is 24 volt. I have plenty of space on the board to mount any type package. I would rather have a closer match for the circuit but in a different package, if possible. I really appreciate your help.

thanks, Gary

Reply to
Gary L. Woodruff

Hmmm. Well, high-power Darlingtons seem to have fallen out of favor with industry - I imagine that power MOSFETs and IGBTs have proven superior - both are easier to drive, and MOSFETs are faster to switch.

I did a search at Digi-Key for NPN Darlingtons, 20 amps or above, in most of the common power packages. The only one they list in a TO-247 plastic package is the ST Microelectronics SGSD100, which is a non-stock item with a big minimum order.

They do have two stock parts by ON Semiconductor - the MJ11016G and MJ11032G (120-volt parts, 30 and 50 amperes respectively). These are both in the classic TO-3 metal package. You'd need to add your own collector/emitter flyback diode.

I just don't think you're going to have much luck finding a high-power Darlington with a built-in diode these days, unless you find somebody who actually happens to have a few New Old Stock parts.

--
Dave Platt                                    AE6EO
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Reply to
Dave Platt

Dave, Thanks for the help. I will try the mj11032g for the higher current. When I look at the data sheet I do see a diode E to C in the schem. I have limited experience replacing with something that is not an exact equiv. I assume a Schottky diode, but what rating, etc? Any knowledge you could impart would be greatly appreciated.

thanks again,

Gary

Reply to
Gary L. Woodruff

Availability is the issue for a 'common' replacement.

A linear part in the same package is NTE92. Although also referred to as a high speed switch, it has no internal base turn-off diode.

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If a TO3 package is practical you might try an NTE97/98/99

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RL

Reply to
legg

You could probably retrofit a TO218 or TO247 body size into place.

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Pinout is the same - youd have to come up with a pressure bar and longer mounting screws.

RL

Reply to
legg

There is nothing magic about a Darlington in one case. A common power bipolar with one or more medium and small signal bipolars and *voila* a power Darlington.

Reply to
Kevin G. Rhoads

Howdy, thanks for the reply. I believe this looks like the most direct replacement for the 2SD829. Correct me if i am wrong but it does not need any other modifications except to mount and dissipate heat?

thanks, Gary

Reply to
Gary L. Woodruff

You need a diode/rectifier which will stand off the maximum battery voltage (with safety margin), and which can handle current peaks of up to the maximum amount of current drawn by the motor (with the worst case probably being when the motor is just starting up or is stalled). The *average* current which the diode will have to handle, will be much lower, since it will conduct only during the moment when the transistor switches off and the diode provides a current-flow path for the energy stored in the motor inductance.

I'd consider something like an IR HexFred diode - maybe the Digikey-part-number HFA30TA60CPBF or similar - it'll handle 30 amperes average and is in an easy-to-mount TO-220AB package.

You might be able to get away with an ordinary power rectifier such as a Crydom CRNA25-400 (25 amps, 400 volts), but since these are going to switch on and off more slowly than a HexFred or Schottky you'd probably see higher peak reverse voltages across the transistor.

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Dave Platt                                    AE6EO
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Reply to
Dave Platt

As a high voltage part, it's saturation voltage when conducting will be higher, and it's gain is also considerably lower, which may stress the drive circuit. A lower voltage darlington should work better.

The NTE270 actually doesn't have better saturation and is also missing the damper diode, but the gain is improved

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What is being switched? If it's not driving a magnetic part in a bridge, the damper may not actually be needed.

Have you checked with the fork lift distributor for replacement parts?

RL

Reply to
legg

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

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?name=MJH11022GOS-ND

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RL

Reply to
legg

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?

Thanks, Gary

Reply to
Gary L. Woodruff

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 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 Platt                                    AE6EO
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Reply to
Dave Platt

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

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circuit diagram. Am I correct that I would NOT need to add a diode to this?

Thanks again, your help is greatly appreciated.

Gary

Reply to
Gary L. Woodruff

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 Platt                                    AE6EO
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Reply to
Dave Platt

Dave, Thanks, I did catch that I needed the 11018 for NPN from the data sheet. The forklift is older and blows this transistor frequently. The factory repair for this is $$$$. If I can replace it with this and it is more robust I can save the company $$$! If this one fails in a short period of time I will try one with a higher current rating and see if that works. Once again thanks to you and everyone else for the advise.

Gary

Reply to
Gary L. Woodruff

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?name=MJH11022GOS-ND

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

RL

Reply to
legg

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