Dimmer for low voltage halogen desk lamp.

I have a couple of these low voltage halogen desk lamps by the bed. My wife wants to put a dimmer on hers. These lamps have a 120-12V
transformer in the base and a diode for dimming down one level. I have replaced the 50 watt bulbs with the lowest power I could find, (I think 25 w), but still not enough.
I know a standard dimmer won't work with the transformer. Is there an off the shelf dimmer that will work? If not what could be suggested as far as an inexpensive and compact autotransformer? I was thinking an isolation transformer wired in a "buck" configuration. I don't think I need a variable. Any pointers?
Thanks
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Joe Leikhim K4SAT
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**THE-RFI-EMI-GUY** wrote:

why not?

a hi temp diffuser in front of the lens such as is used for theater lighting.
the most popular makers are http://www.gamonline.com/index.php and http://www.rosco.com /
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I thought of that but these lamps are counterbalanced in a funky way and adding anything to them causes the lamp head to fall.
TimPerry wrote:

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I thought of that but these lamps are counterbalanced in a funky way and adding anything to them causes the lamp head to fall.
TimPerry wrote:
**THE-RFI-EMI-GUY** wrote:
I have a couple of these low voltage halogen desk lamps by the bed. My wife wants to put a dimmer on hers. These lamps have a 120-12V transformer in the base and a diode for dimming down one level. I have replaced the 50 watt bulbs with the lowest power I could find, (I think 25 w), but still not enough.
I know a standard dimmer won't work with the transformer.
why not?
Is there an off the shelf dimmer that will work? If not what could be suggested as far as an inexpensive and compact autotransformer? I was thinking an isolation transformer wired in a "buck" configuration. I don't think I need a variable. Any pointers?
Thanks
a hi temp diffuser in front of the lens such as is used for theater lighting.
the most popular makers are http://www.gamonline.com/index.php and http://www.rosco.com /
- Joe Leikhim K4SAT "The RFI-EMI-GUY"
Joe, I use dimmers with quartz lamps all the time. granted they are 500 to 1,000 W each (theater lighting) but i fail to see why a small desk lamp would have a problem with an off the shelf hardware store dimmer.
73's - Tim
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The transformer will buzz like crazy
TimPerry wrote:

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**THE-RFI-EMI-GUY** wrote:

replace bulb with white LED's ?
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Thats an idea!
TimPerry wrote:

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wrote:
| I have a couple of these low voltage halogen desk lamps by the bed. My | wife wants to put a dimmer on hers. These lamps have a 120-12V | transformer in the base and a diode for dimming down one level. I have | replaced the 50 watt bulbs with the lowest power I could find, (I think | 25 w), but still not enough. | | I know a standard dimmer won't work with the transformer. Is there an | off the shelf dimmer that will work? If not what could be suggested as | far as an inexpensive and compact autotransformer? I was thinking an | isolation transformer wired in a "buck" configuration. I don't think I | need a variable. Any pointers?
Probably not what you want, but it might be fun :-)
http://phil.ipal.org/usenet/aee/2006-11-02/dimmer-1.jpg
http://phil.ipal.org/usenet/aee/2006-11-02/dimmer-2.jpg
http://phil.ipal.org/usenet/aee/2006-11-02/dimmer-3.jpg
http://phil.ipal.org/usenet/aee/2006-11-02/dimmer-4.jpg
http://phil.ipal.org/usenet/aee/2006-11-02/dimmer-5.jpg
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|---------------------------------------/----------------------------------|
| Phil Howard KA9WGN (ka9wgn.ham.org) / Do not send to the address below |
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A little big to put by the bed!
snipped-for-privacy@ipal.net wrote:

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And it's the wrong voltage ... unless you are using 480 volt HID lamps :-)
wrote:
| A little big to put by the bed! | | snipped-for-privacy@ipal.net wrote: |
wrote: |> |>| I have a couple of these low voltage halogen desk lamps by the bed. My |>| wife wants to put a dimmer on hers. These lamps have a 120-12V |>| transformer in the base and a diode for dimming down one level. I have |>| replaced the 50 watt bulbs with the lowest power I could find, (I think |>| 25 w), but still not enough. |>| |>| I know a standard dimmer won't work with the transformer. Is there an |>| off the shelf dimmer that will work? If not what could be suggested as |>| far as an inexpensive and compact autotransformer? I was thinking an |>| isolation transformer wired in a "buck" configuration. I don't think I |>| need a variable. Any pointers? |> |>Probably not what you want, but it might be fun :-) |> |>
http://phil.ipal.org/usenet/aee/2006-11-02/dimmer-1.jpg
|>
http://phil.ipal.org/usenet/aee/2006-11-02/dimmer-2.jpg
|>
http://phil.ipal.org/usenet/aee/2006-11-02/dimmer-3.jpg
|>
http://phil.ipal.org/usenet/aee/2006-11-02/dimmer-4.jpg
|>
http://phil.ipal.org/usenet/aee/2006-11-02/dimmer-5.jpg
|> |> |> |
--
|---------------------------------------/----------------------------------|
| Phil Howard KA9WGN (ka9wgn.ham.org) / Do not send to the address below |
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snipped-for-privacy@ipal.net wrote:

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Most normal dimmers are not designed to work well with highly inductive loads like traditional transformers.
Electronic transformers used on many modern low voltage halogen light systems. Those are switch mode power supplies. Dimmign them varies from not dimmable, to dimmable with special dimmer to dimmable with normal dimmer.

I don't know what is "off the shelf" in USA where you live.

Autotransformer method will work with halogen lights that use normal traditional transformer.
The dimming range that you cam get with adjustable autotransformer with "electronic transformers" can vary from quite useable to not workign very well depending on the "electronic transformer" type.

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Tomi Engdahl (http://www.iki.fi/then /)
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