Pictures - possibly done before

[danf1966]

mini solar panel

 

[Marvo]

Kinda looks lka a group head filter out of my espresso machine.

 

[Besoeker]

Kinda looks lka a group head filter out of my espresso machine.

View attachment 25810

Yes, I can see as visual similarity between the images.

 

[Richard Burns]

Since you have a continuous high surface area barrier separating two substrates one assumes that, since it is not a capacitor, that it is another form of energy storage, battery or such like.

 

[not clever]

I'll go for; it's a sensor of some type
Heat maybe?

 

[Besoeker]

Since you have a continuous high surface area barrier separating two substrates one assumes that, since it is not a capacitor, that it is another form of energy storage, battery or such like.

Possibly the closest so far.
My wife, non-technical, got it right after but a moments thought*.

It's a four layer semiconductor device. The chip from a fairly large silicon controlled rectifier, SCR.
A thyristor. In this case, an inverter grade device. The convoluted pattern is the gate.

A little explanation addendum from an old fart if I may.
As many of you probably already know, thyristors are like diodes. But three terminal devices. They conduct in the forward direction only. The difference is that they don't conduct at all until that third terminal is given a bit of tickle. A volt or so is enough to kick them into conduction.

Applications range from battery chargers to HVDC transmission. So, a useful and versatile thing.
I mentioned tickling the gate with a volt or so. That's fine for small devices. But not so much for the larger chips like the one I pictured. The gate pulse initiates anode to cathode current flow. In about 1us or less. And initially, in the region of the gate. The spread across the whole area of the chip is a bit slower and can result in hot spots. (di/dt limitation)

To avoid this problem for demanding applications, the gate path is extended. That's what my pic of an actual device shows.
The convoluted pattern is the gate extending its tentacles across the area of the chip.

Riveting stuff, I know.......

*she has seen that actual device on my desk.......

 

[ferg]

Since you have a continuous high surface area barrier separating two substrates one assumes that, since it is not a capacitor, that it is another form of energy storage, battery or such like.

RB if at any time you would like to be ill informed or wrong about anything could you please give either myself or TC advance notice so we can read up on the subject......

And still be confused

 

[Bobster]

It's an SCR thyristor.

Made with some really horrible chemicals.


Edit: Threads already been answered. Seems I'm a little slow.