[sci.electronics] Transformer current ratings

bm@bike2work.Eng.Sun.COM (Bill(Francis) Michel) (03/02/91)

I want to build a power supply for a halogen lamp that uses 55 watts. This
is a 12v lamp. THis means somewhere around 4 amps, right? But when I go
to buy a transformer, the ratings they give (in amps) apply to a certain
number of amps, but I'm not sure whether that means through the primary 
or secondary windings?

Can someone clear me up on this?

If it's through the primary, how do I calculate the needs of my system,
given what I know about the secondary circuit.


Thanks

Bill
--
Bill Michel			
bm@eng.sun.com		These views are my own, not Sun's.

verive@tellabs.com (Jeff Verive) (03/03/91)

In article <8927@exodus.Eng.Sun.COM> bm@bike2work.Eng.Sun.COM (Bill(Francis) Michel) writes:
>I want to build a power supply for a halogen lamp that uses 55 watts. This
>is a 12v lamp. THis means somewhere around 4 amps, right? But when I go
>to buy a transformer, the ratings they give (in amps) apply to a certain
>number of amps, but I'm not sure whether that means through the primary 
>or secondary windings?
>
>Can someone clear me up on this?

Transformers are rated in secondary amps (BTW, 55W/12V is more than 4A, and
it's not a bad idea to be conservative with transformer ratings. Helps keep
them cool and happy.)

 
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**   Jeff  Verive  |  If they ever stop making those little candy flowers **
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