🚀 go-pugleaf

ahamad@kuhub.cc.ukans.edu writes:

>I have a question
>I have been working with circuits for quiet some time now. I have noticed
>a phenomenon of difference in color of the sparks at the switches depending on
>the type of current used.
>for the DC the sparks are brilliant white
>for the Ac the sparks are blue with touch of yellow

I used to muck around with high-voltage equipment quite a lot, and I haven't
noticed much difference.  I get a lot of blue-white sparks, some with green
tinges (I expect from copper contacts), but no consistent difference between
AC and DC sparks.

Besides, I wouldn't expect any low-frequency differences like 50 or 60Hz to
make much difference in sparks that have millisecond duration.

> please note that I did not have a capacitor in the circuit(honest)
>and this seems to hold true for comparable voltages

*What* comparable voltages?  DC voltages are pretty unambiguous (unless you
have non-negligible inductances in the circuit - just try to get rid of them!),
but AC voltages come in RMS, Peak-to-Peak, half-peak, and a few less-well-known
ones.

>I have been using this phenomenon of observing the sparks and figuring
>what type of current the circuit carries when I dont have a meter handy
>(not a good practice, I have fused many a I.C by not being carefull , but beats
>the method of working blindly) 

It does?  What are you doing, that knowing whether a circuit carries AC or
DC (or a mixture) is important enough to destroy parts of the circuit?

Hmm - what sort of circuits are we talking about here, anyway?
Are we talking 5V, mains power, or HV stuff?

>also note it is possible to figure if the circuit has both the components ( Ac
>and DC)
> dose the key lie in the fact that a lamp on dc gives white (?) light compared 
>to lamp run on ac pale yellow ?

For the same mean power, both seem to give about the same colour light to me 
(now talking about 12V incandescent lamps, since 240V DC high-current sources
are not easy for me to find, and HV tends to blow lamps - AC or DC).


This probably appears skeptical and negative, maybe I could be more helpful if
you gave more data on what you are doing.
--
T. Little   a.k.a.   u894793@bruny.cc.utas.edu.au