Re: Solid State

Hi Alan,
         You wrote (apologies for the reformat)....

> I reduced the sensitivity of the current limiter, and I've beening
> trying different transformer ratio's. Good results at 8:1 step up.
> 12:1 was great fun - 5A current meter off the scale very energetic
> sparking but after a few minutes my 5A fuse blew (not surprisingly
> and when I put the main light on I saw a little bit of smoke from
> the output transformer. Windings very hot (core ok). Electronics
> were still fine though output transistors barely warm, transformer
> checks out ok and I'll try another short run when its cold.

Have you thought about using copper strap for the primary? It is a
preferred conductor choice for high current windings in SMPS 
   Secondly, you said the core was O.K. I believe you're using 3C85
material. An even better one is the Philips 3F3 material (good for 
the MHz range and quasi-resonant supplies.

> A surplus store is selling lots of small toriodal
> cores - no information on the core materials
> only that some are red, or blue or natural -
> is there a colour code for these things?

A thought on using ring cores or U-cores etc. You can stack these to
effectively make much bigger cores. I've seen this technique used in 
RF power amps.