Re: Dumb question ...

George wrote:
Sounds to me that the lamp is going to try to get its 10 Amps and will blow up the transformer.
George


"Daniel" <dxmm@xxxxxxxxxxxxxxxxxx> wrote in message news:465fe984$0$16345$88260bb3@xxxxxxxxxxxxxxxxxxxx
Watts is Power measure in DC circuits where as VA is power measurement (sort of) in AC circuits because of possible phase shifts between the applied voltage and the Current.

If, and that's a very big IF, the circuit is PURELY resistive, the the AC Power will be the same as the VA rating.

40 VA transformer can, usually, very easily drive a 250 W lamp, but the lamp will, most likely, be fairly dim.

Daniel



<snip>

The lamp will try to draw its 10.4 amps, but the supply cannot deliver that much, so the voltage out of the supply will drop.

The 40 VA does NOT mean that it can supply 24 V at 1 A. It can provide 40 VA, which could be 0.5 A at 80 V, 2 A at 20 volts, whatever the output of the Supply is set to provide, so it may be that you are connecting your 250 V lamp to a supply that only gives 40 volts, so the lamp will only be one sixth as bright a it could be, if it were connected to the right supply, something that can deliver 250 V at upto 1 amp.

Daniel

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