powerbuy
Active member
I have boxes of surface-mount transistors like the ones shown in the photo. Do these have any values or PMs making them worth saving?
Surface Mount Transistors
- Thread starter powerbuy
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Maybe, but I doubt it. These TO3s have been made in several different ways over the years - all gold plated, only the base and legs gold plated, and with no gold plating, to name a few. Since I see no gold plating on these, I think that about the only thing you might find is a little silver solder under the chip. If so, they are not worth messing with. The chip can also be attached with epoxy. Cut one open and see what's under there.
I just noticed that the one at the bottom appears to have some sort of solder attaching the lid. The color is copperish and there is a slight possibility that it could be a copper/silver braze. File some off and test the filings. Add a little nitric and a equal amount of distilled water to dissolve the filings. Heat if necessary. Add a drop of HCl or salt water to the solution. The presence of a white cloud would indicate silver. Even if it does contain silver, recovery would probably be difficult, depending on what the base metal is.
I just noticed that the one at the bottom appears to have some sort of solder attaching the lid. The color is copperish and there is a slight possibility that it could be a copper/silver braze. File some off and test the filings. Add a little nitric and a equal amount of distilled water to dissolve the filings. Heat if necessary. Add a drop of HCl or salt water to the solution. The presence of a white cloud would indicate silver. Even if it does contain silver, recovery would probably be difficult, depending on what the base metal is.
powerbuy
Active member
So these are most likely silicon and steel? I didn't see any gold, but thought that there might be Platinum or palladium somewhere in them, although logically it wouldn't really make sense. I'll cut one open today, although even if there's a little silver solder they still are probably not worth saving. I'll probably throw a huge lot of them up on Ebay for hobbyists or something.... maybe get a few bucks that way.
I doubt if they are steel, although, I guess, they could be. They are probably nickel plated copper, aluminum, or Kovar (54Fe, 29Ni, 17Co), which is magnetic. Some of them have a big chunk of copper on the inside. It looks like you have an assortment.
most of the time, these are voltage regulators (example unregulated 24volt dc input will give a regulated +12 volt dc output), or current regulators, or higher current transistors for switching or to amplfie, inside those TO-3 packages, they are great for building power supply's audio amplifier's with. if you want to use them, or want to know there use, just google the number and type data sheet after the number. that will give you specifications, and most of the time you can also get application notes of circuits with diagrahms of circuits that are popular for there use. and if you did want to build a power supply you can easily find a circuit that will fit your specifications. oops this is not an electronics sight.
