Electronic transformer ? 2

[walker1]

I have seen that you can get electronic transformers for halogen lighting these days.

However, nobody wants to say much about what comes out of those.

It seems the device is switching internally at 20 kHz or so,
but do you connect the bulb directly to the secondary output of
the switch transfornmer ?

I would not use that in a sensitive environment. The EMC fields must be huge !

Or is the output somewhat rectified / filtered like a SMPS ?

 

[electricuwe]

I think the output is rectified, but not smoothed like in an SMPS. Without rectifier the electronic transformer wouldn't be able to supply power to halogen systems having high inductance between transformer and lamp because of the spacing between the two conductors.

 

[sfardella]

The electronic transformer can be used to power various lamp types - the advantage is variable output power. I am familiar with electronic transformer being used to run mercury vapor lamps - the output is, as you state, in the 20khz range but is typically a modulated signal if it is desirable to vary output power. Voltage output is dependent on lamp type. EMC is definitely an issue but any commercial manufacturer will take steps to keep amount of EMC within compliant levels. Look for the CE mark on the product.

 

[jbartos]

Suggestion: Visit

http://www.pegasusassociates.com/products/Transformers/trans.html

etc. for more info

 

[jraef]

walker1,
Essentially, the electronic ballasts used for lighting fixtures now ARE a type of SMPS. EMI and harmonics are big issues with these devices and not all manufacturers take this seriously, especially those selling on price. As sfardella mentioned above, a CE mark is a good first step in selecting a ballast because CE requirements are very stringent in this regard and manufacturers nust add filtering in order to comply. US manufacturers who are not exporting however do not need to meet CE requirements, only FCC regulations which are concerned about RFI, a different issue.
Quando Omni Flunkus Moritati

 

[Aranrhod]

I came across a commercial (?) system a few years ago which used high frequency AC on long wires to drive remote compact fluoros I think, round your garden. It didn't work at all well over long (20+ yards !!) distances. Just work out the likely standing waves at near megahertz frequencies. Wonder if it's still marketed . . .