Identification of Electrical Item

[jevoltin]

I need help identifying an item distributed by Precision Scale Co. based in Woodland, CA. I have two packages each containing one item as shown in the attached photo. For the photo, I removed one item from its package and left the second in the package. The packaging provides no identification of this item and there are no instructions. The package does specify "O/S/HO" Scale, so this is clearly a general purpose item. It has been suggested that this is a constant light circuit, but I don't understand how that's possible. I performed the standard electrical tests on this item, but they were inconclusive. The two metal leads seem to be directly tied together.

Does anyone recognize this item?

 

[ezdays]

I can't ID this by looking at it, maybe someone knows from having used it. But the first thing I might ask is are there any markings on the device itself? There should be something like: "2Nxx" and a date code.

My first guess is that it might be a unijuction transistor, but I've not ever seen a device with a wire attached to the back like that.

Oh, and welcome to the Gauge.

 

[jevoltin]

I should have mentioned this in my original posting. There are no markings on the device itself. Even under magnification, I could not find any markings, logos, etc. The black wire actually exits the side of the device. The two short protrusions on the top (one is notably shorter than the other), were molded with the shell.

 

[jevoltin]

By the way, thanks for the suggestion. I will look into unijunction transistors and similar devices.

 

[ezdays]

Those protrusions are most likely a heat sink, and might electrically be attached to the wire coming off the side.

A unijunction, perhaps an SCR, it's a pity that there are no markings on the device or the package to give you a clue. The package looks old so it has got to be an older device. That doesn't mean it's not good, we just don't know what it's good for right now...

 

[Iron Horse]

Isn't precision scale co. still in business ? Try emailing them. They should know what it is if they made it, right

 

[jevoltin]

Good suggestion. I have sent the photo to Precision Scale Co. I will post any feedback to this forum.

 

[Clerk]

I live in Esparto, about 20 miles from Woodland. I just checked the phone book, both yellow and white pages and no listing. I don't ever recall a company in Woodland by that name. There have been several that moved in and after a short time left. It could have been one of those.

 

[jevoltin]

I do not know if they are still located in Woodland, CA, but here's their current web site: http://www.precisionscaleco.com/ The current address is in Stevensville, MT. My items came in packages with the Woodland, CA address. I do not know the age of these items, so they may have moved many years ago. Based upon the logo shown on the package, I believe this is the same company.

 

[kf4jqd]

If it is for constant lighting. It could be a voltage regulator. It looks like a 7805 regulator. It could be a transitor. There should be markings on it. That would help. In in picture, it looks like it's incased with heat shrink tubing.

Andy

 

[ezdays]

If it is for constant lighting. It could be a voltage regulator. It looks like a 7805 regulator. It could be a transitor. There should be markings on it. That would help. In in picture, it looks like it's incased with heat shrink tubing.

Andy

I kinda doubt that it's a regulator, I've never seen one with only two legs, unless someone has cut off the common leg and soldered a wire to the heat sink tab (electrically the middle leg). That makes little sense to do that, but on the other hand, I've seen some people do stranger things than that...

 

[kf4jqd]

I see that black wire is connected to the center part of whatever that is. That is ground for most regulators. Best is to check with the manufacture.

Andy

 

[cidchase]

I wonder if it could be a lighting pickup for a pass. car or caboose, etc.,
with the two leads bent to wipe on metal axles, and the wire to lead up
into the car body. Does that count as a W.A.G.???

 

[jevoltin]

I doubt this is a voltage regulator because its relatively small. The rectangular body measures .290 high by .190 wide by .068 thick. The hole is .080 in diameter. The result is a fairly small volume. The two protrusions on top are extremely small - only .011 in diamter. Although it is unclear from the photo, this item is not covered with heat shrink. The body is clearly molded - the parting line is readily apparent on the sides. All voltage regulators I have seen are much larger and include some form of heat sink. Are there any voltage regulators that are this small and don't generate much heat?

 

[jevoltin]

This might be some sort of power pickup for lighting a caboose, passenger car, etc. I don't understand the reasons for the particular construction, but that doesn't mean much.

 

[jevoltin]

Is there any simple way to test a component to determine if its a voltage regulator? I have examined this item with my DMM, but that didn't tell me much. I do have a LCR meter available. Could that be used to learn anything?

 

[ezdays]

I doubt this is a voltage regulator because its relatively small. The rectangular body measures .290 high by .190 wide by .068 thick. The hole is .080 in diameter. The result is a fairly small volume. The two protrusions on top are extremely small - only .011 in diamter. Although it is unclear from the photo, this item is not covered with heat shrink. The body is clearly molded - the parting line is readily apparent on the sides. All voltage regulators I have seen are much larger and include some form of heat sink. Are there any voltage regulators that are this small and don't generate much heat?

There are, like a 78L05 is in a TO-92 case, a small transistor, but with three legs. I found a TO-251 package that looks similar to yours, but again, there are three legs. Most any semiconductor device can be packaged in it, so there would still be no way of knowing. what it is without some markings on it.

Good luck, this is intriguing to say the least, keep us posted on what the company says. I'm sure they didn't manufacture it, they just put it in the bag for resale. Some companies purposly remove manufacturer markings to keep others from copying their application of that device. They may pay a quarter for it then put it in a bag and sell it to modelers for five dollars as a (whatever) and they don't want you to know what it is. But at least the bag should have a company part # on it somewhere.

 

[hooknlad]

Im going with Dons idea of some type of transistor... Does Mouser have transistors in its catalog?.

 

[ezdays]

Im going with Dons idea of some type of transistor... Does Mouser have transistors in its catalog?.

Yeah, only a few hundred pages of them. I checked their catalog and that's where I spotted that TO-251. It was under MOSFETs and a few other transistors, but all with three legs. There was a TO-252 configuration that is surface-mounted and only had two short legs and used the heat sink as the third connection. But clearly, you can see where the middle leg was cut off.

 

[jevoltin]

I compared this item to some of the standard transistor packages and discovered that there are some similar packages, although none of the standard packages have a large hole through the part. Both SP-8 and SST packages are about the right size. Of course, these transistor packages have three legs. How unusual would it be for this to be a non-standard package?