Hello everyone, does anyone know what this is? Is it a laser trimmed thermister?

 

Do we get any clues?
What is it out of?
How big is it?
Does it have any wires attached to the back? If so, how many?
What is it made of?
Have you made any electrical measurements on it?
Is this part of something?
Did it have a cover on it?

 

Why waste time on details? Google search revealed this.

 

Do we get any clues?
What is it out of?
How big is it?
Does it have any wires attached to the back? If so, how many?
What is it made of?
Have you made any electrical measurements on it?
Is this part of something?
Did it have a cover on it?

Sorry Keith.
So its out of an ignition module for small engine. It has a mega ohm resistance beween the two solder points, that drops to k ohm with heat. Could it be a overheating sensor resistor? It has a thin copper plate as a base...

 

Looks like some sort of semiconductor device-- transistor, MOSFET, SCR, TRIAC, etc...

 

That is a BJT transistor. A Darlington I suspect.

It helps when you have a background in hybrids, or worked at a transistor foundry. I've done both. ;-)

 

That is a BJT transistor. A Darlington I suspect.

It helps when you have a background in hybrids, or worked at a transistor foundry. I've done both. ;-)

Thanks Ernie. It only had two solder points... should not there be 3?

 

Thanks Ernie. It only had two solder points... should not there be 3?

Nope. Just two. The collector is the backside.



Here's one in a TO-3 case. The TO-3 case is the collector so having the whole backside of the die being the collector means you can mount one to another for the best electrical and thermal conductivity.

 

Thanks Ernie. It only had two solder points... should not there be 3?

Nope. Just two. The collector is the backside.

View attachment 203965

Here's one in a TO-3 case. The TO-3 case is the collector so having the whole backside of the die being the collector means you can mount one to another for the best electrical and thermal conductivity.

Wow!! That is cool !
Thankyou .. which one is the base and emitter?

 

Hold a TO-3 in your hand with the leads up towards your face, with the mounting hole closest to the leads towards you. Call that mounting hole "home."

Now run to first BASE.

Sometimes you can tell by the wire bond size as the base doesn't need to carry a tenth of the current of the emitter. About. Here both wires are the same size as the aluminum wires used don't cost enough to justify a secondary operation.

Anyway, the smaller feature on the lower side is the base, emitter the rest of the top, and the collector is on the bottom.

 

Based on the wiggly shape, it makes me think of delay lines, or PCB RF antenna's, but that's WRONG LOL

 

Based on the wiggly shape, it makes me think of delay lines, or PCB RF antenna's, but that's WRONG LOL

Thanks Darth.... that was my line of thinking at the beginning !!

 

I don't know what it is, but it reminds me of a member's icon.