OT: Power BJT Power Limit

And PolyZens have all gone away. *sob*

Yup.

Cheers

Phil Hobbs

When I was a kid I used a teakettle as the ballast in an arc lamp made from the carbons of two D cells arranged inside a large Colman's mustard tin. That sucker was _bright_. My parents had lots of stomach lining. ;)

Cheers

Phil Hobbs

The Sinclair Z12 was no better - in fact probably worse. I bought one in late 1968 and soon found out it went into a sort of motorboating distortion after barely 30 minutes. Well, what would you expect with reject germanium power transistors (were they OC26?) and a totally inadequate heat sink?

I should have known better after my experience with the Z12, but I bought a QL in September 1984. It actually worked quite well, especially with the extra 500k of ram I bought. But, of course, the famous Sinclair reliability issue came into play when one of the Microdrives failed - the one that loaded the OS, of course, so the machine became unusable. Not long after I started using an IBM desktop at work (386 running DOS

Sinclair's reputation was that his audio products were dreadful; there were many many bad stories in the letter columns of the electronics magazines.

Even though I would have been perfectly capable of assembling it myself, that reputation made me buy an assembled and working Sinclair Scientific calculator.

It still works, and is as accurate as a slide rule - which is a remarkable achievement considering /everything/ was contained in a 320 instruction ROM. Ken Shirriff has an online simulator, which is worth a look.

The IC10 claimed to be a 10W amplifier, but it was a rebadged Plessey chip rated by Plessey at something like 3.5W.

I had one of those. It was horrible as it could sometimes give results that were much less accurate than a slide rule. I was caught out when dividing a number by the difference between two similar numbers. I think the error was several percent. This was a problem because I didn't notice at the time.

John

I seem to remember something similar, but when I tried what I remembered, the answer was correct.

If you don't have a working Scientific to hand, you could try to repeat the experience on this notable emulator

I would first have to find my physics practical lab notes from 1977. They were almost certainly binned a very long time ago.

John

When, around that time, I had to do lab calculations, I tended to go to the university library and use the HP35. It was carefully bolted to the librarian's desk :)

Now I have one of my own, in a hand-crafted hardwood box.