Sometimes manufacturers will do this with flame-proof resistors that are
there simply as a fuse in case of a short circuit else where drawing
excessive current. Perhaps they are a few cents cheaper than a fuse.
Rolf wrote:
{Quote hidden}> Hi all.
>
> Looking for some insight as to the purpose of a resistor in a desk
> lamp... specifically, an illuminated magnifier, 120V AC lamp that has a
> circular Flourescent tube. The lamp was not working, and I tracked it
> down to a failed-open resistor, 0.1 Ohm 5% 1W in series with the live AC
> current.
>
> 120V live wire>--------------/\/\/\/\/\/\-------->to rest of circuit
> 0.1 Ohm
>
> With the resistor failed open, the circuit of course does not work. The
> resistor is not a current-sense resistor (there is no sensing circuit).
> I have bypassed/shorted the failed resistor, and (briefly) tested the
> circuit, and it all works (the light goes on... ;-).
>
> I intend to replace the resistor with an equivalent (but higher power
> rating), but my curiosity demands that I understand why there would be a
> 0.1Ohm resistor in series with Live. The best I can figure would be a
> current/surge limiting resistor, but I would have thought it would be a
> higher value. I was hoping for some other suggestions/confirmation.
>
> Thanks
>
> Rolf
>
>
