An old power transistor

Images taken in a controlled environment or with a posed subject. All subject types.

Moderators: rjlittlefield, ChrisR, Chris S., Pau

Bob-O-Rama
Posts: 200
Joined: Sat Dec 06, 2014 6:46 am
Location: Allentown, PA, USA, Earth, etc.
Contact:

An old power transistor

Post by Bob-O-Rama »

I found a few very old power transistors and popped the top off of one to look at the guts.

Image

The crop is a bit severe as the minimum magnification of the rig is about 2x without pain.

One thing I struggle with is getting a "black enough" black for backgrounds. I got a small bottle of a Vanta Black knockoff, "Black 3.0" by Culture Hustle. I was... skeptical. But this stuff is amazing, and I use it for everything from coating optical tubes / extensions / hoods, also masking off reflective surfaces on subjects or making dodges. The background is a piece of cardboard with two coats.

The wafer is an extremely thin circular disk about 4mm is diameter. It has an unusual surface texture, and at some angles looks like blued steel.

Image

( Not my favorite take, but this is what I'm, talking about. )

Image

The surface is poly crystalline in appearance. While individual sills have very sharp detail on pixel peeping, the surface were low contrast and very smooth, I had trouble getting Zerene stack them.

Image

"Hey, lets slap some solder on it!" mounting asthetic. Compared to slice and dice dies from even the 1970's this looks rustic.

Image

The underside of the wafer has a gold band around its perimeter, attached to the bond wire as seen in these crops.

Image

Image

Here is a hasty 20x of the bonding. ( It was laundry day, this shot was plagued by tremors, and dust, and... excuses. )

Image

I am pretty sure this is a form of alloy junction ( so 1950's ) where the doping agent is in the form of the bright indium solder on either side - but I am confused by the texture. I think the wafers would be slices of mono crystalline N-type material, and they get acid etched to remove crazing from the wafering process. So perhaps those are not crystal boundaries. IDK. If anyone does, let me know. The transistors themselves are in TO-looking packages, but have no identifying marks, some are gold plated, others have no plating at all and are just copper.

JayMcClellan
Posts: 124
Joined: Thu Nov 24, 2022 8:50 pm
Location: Saranac, Michigan
Contact:

Re: An old power transistor

Post by JayMcClellan »

Hey that's really cool, and nice quality pics. I can't help but wonder what it would look like after being overloaded to the point of destruction. Maybe there wouldn't be much left to see but it could be interesting.

Marcepstein
Posts: 293
Joined: Thu Oct 13, 2022 8:39 pm
Location: USA
Contact:

Re: An old power transistor

Post by Marcepstein »

Nice images :!:

Post Reply Previous topicNext topic