Transformer alternatives - Page 2 - Electronic Circuits Projects Diagrams Free

rmn_tech · 16th May 2008, 11:01 PM

Quote:

Incidently, the worlds first domestic use of a SMPSU was in the Thorn 3000 colour TV about 1972 or so?.

I remember the 3000 chassis. Now with a fond recollection, but at the time I hated it. More than 80% of the faults were P.S.U. faults, not so bad when you had your list of stock faults. (On paper or in your head no computers as such then).

Rick Br@nchTV.

**Nigel Goodwin** · 17th May 2008, 09:14 AM

Quote:

Originally Posted by rmn_tech

I remember the 3000 chassis. Now with a fond recollection, but at the time I hated it. More than 80% of the faults were P.S.U. faults, not so bad when you had your list of stock faults. (On paper or in your head no computers as such then).

I loved it back then as well, I built a jig for repairing 3000 panels, and one for repairing Bush A823 panels as well - I've no idea how many panels I repaired over the years, but it was a LOT!

Ubergeek63 · 17th May 2008, 06:06 PM

Quote:

Originally Posted by Optikon

The physical size of a transformer is governed by its losses, not the power that is "transformed" from input to output. Losses typically consist of resistive, eddy current & core (magnetic). Controlling these in your design will determine your maximum power rating.

Which is a nice theory. In practice, resistance and core losses go up as dimensions go down. And like every good law, there is an exception: At very high frequencies the resistance goes up again due to the skin effect.

Quote:

A typical "offline" switchmode converter will first rectify and smooth the line thus creating a high voltage DC. From there, a PWM method is used on a flyback transformer to generate the right output (typically)

Flybacks are normally not used at high power. The reason is that you can get twice as much power through a core in a bridge topology.

The http://www.ferroxcube.com/prod/assets/e22616.pdf can run around 100W flyback or 200W push-pull, and the http://www.ferroxcube.com/prod/assets/e641050.pdf can pass 3KW!

RODALCO · 18th May 2008, 10:39 AM

Sorry for my earlier reply, I must have been tired, and thought you needed a high current DC supply.

I didn't read your question correctly and missed that you were after a high current AC supply.

As already said by our other members, an autotransformer is lightest but the output is not galvanically separated from the mains supply.

Regards, Raymond

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18th May 2008, 10:39 AM	(permalink)
RODALCO	Smps Sorry for my earlier reply, I must have been tired, and thought you needed a high current DC supply. I didn't read your question correctly and missed that you were after a high current AC supply. As already said by our other members, an autotransformer is lightest but the output is not galvanically separated from the mains supply. Regards, Raymond __________________ There are more ways to get to Rome. Electricity, Electric clocks, Meters and Trains are great.