JEDEC TO-121 NPN Bipolar Junction Transistor

In this video, I take a closer look at some odd looking devices. When I first got them from Ebay, I had no idea what they were, but I suspected them to be transistors because of the three leads present. I was able to confirm that these are NPN Bipolar Junction Transistors with the help of a component tester.

I had never seen a package like this before, so I started digging to find out more information about it. After not finding anything about them, I resorted to signing up for an account on the JEDEC website, the group responsible for maintaining and creating Transistor Outline specifications, among other things. On the JEDEC website they have links to almost all of the Transistor outline specifications, starting with TO-1.

Eventually I made it to TO-121 and I found a match! The specification here shows the outline of a four-terminal device, but does allude to three-terminal devices as well, which is what I have here. The most interesting thing that I saw on the spec was that it was first released in 1967, and I'm not sure if it was ever updated after that.

The chip inside is also very interesting. The wires that were used to bond the chip to the terminals are MASSIVE, and might be the biggest that I've seen in a component of this size.

Video Chapters:
0:26 - Transistor Outline
0:42 - Opening the device
1:23 - Looking at what's inside!
2:37 - Testing the device
4:17 - Support the channel!

Quick Links!
---------------------------------------------------

🔬 Join the ChipChat Discord Server!
---------------------------------------------------

Check out my Social links!
---------------------------------------------------
📷 Instagram:
-
🎥 TikTok:
-
🐦Twitter:

Stop by my website to purchase some PCBcoins, Silicon wafers, and more! Each purchase helps fund the work I am doing to document more chips.
---------------------------------------------------
🛒Website Store:

All music used in this video is AI generated and licensed through a Soundful Premium Subscription.

[here_is_Peet]

Man if you wouldnt post videos my hobbie never existed! You introduced me to the nanotechnology. You thaught me that how beautiful and impressive these things are! LOVE YOUR VIDEOS!!!❤

[Jermungand]

Don't know if you know this, but opening up transistors allows light to influence the characteristics of them. Turning them into light detectors. Maybe that's why the one you opened up tested differently.

[TrapperAaron]

I luvs ur ruler! Got a couple of em myself from T.I. back in the day. They used to ship them w every purchase! Infact they used to ship all kinds of goodies even w small purchases. Then again banks used to give away cars and toaster ovens.

[googleevil]

One of the best on YouTube! Thank you!

[drdyna]

Oh man I would love to get my hands on some of those!

[TrapperAaron]

One of my favorite multimeters is actually the ones they give away for free at harbor freight. They used to be really nice analog sets w zero adjustment dial and 2 sets of leads (probe and alligator style). The new ones are digital and onlybcome w a probe style lead. But they kept the transistor test bed function in the form of a little circular part w holes for pnp and npn transistor checking. I get one every time i goto hazard fraught and keep a brand new one in my box of test equipment to give to friends and family w no multimeters at all. Its better than nothing and a great deal for free!

[lelsewherelelsewhere]

Are there "wobble" attachments to show 3d perspectives of microscopic samples? (For the odd case of 3d shapes, like that pressed wire)

[mrga]

I think they are high frequency power transistors. Supposed to be used in stripline applications. I'm probly wrong but i did work with things that looked like these back in the 1980's.

[meaninthemirror]

Very high quality. I would like to build an audio amplifier with those transistors.

[alexwang]

That hFE is tiny... Must be a pretty high powered transistor then, would be interesting to see its datasheet for its intended use!! Fascinating

[richardlangdon]

Were these used in ICBMs or some sort of hardened military gear? They look very rugged.