nalen Posted September 22, 2005 Report Posted September 22, 2005 GUYS HOW R-L-C EFFECT HARMONIC RESONAN....CURRENT???? :P Quote
audioguru Posted September 22, 2005 Report Posted September 22, 2005 Hi Nalen,Please think about it.Parallel Resonance.Don't you think that a parallel resonant circuit is supposed to be a high resistance at resonance?What happens to it and its attenuation of harmonics if it had a low resistance across it?Series Resonance.Don't you think that a series resonant circuit is supposed to be a low resistance at resonance?What happens to it and its attenuation of harmonics if it had a high resistance in series with it?[move] ??? ??? ??? ??? ??? ??? ??? ??? ??? ??? ??? ??? ??? ??? ??? ??? ??? ??? ??? ??? ??? ??? ??? ??? ;D[/move] Quote
nalen Posted September 22, 2005 Author Report Posted September 22, 2005 anyone know how to represent floresence lamp using RLC....anyone?thankaudioguru Quote
audioguru Posted September 22, 2005 Report Posted September 22, 2005 The ballast of a florescent lamp is a current-limiting inductor. An inductor has inductive reactance to AC which is like a resistor without loss (without much heating).I haven't seen a capacitor nor resistor in a florescent light's ballast. Without a capacitor with the inductor then it doesn't resonate. Quote
Guest Alun Posted September 22, 2005 Report Posted September 22, 2005 audioguru,Capacitors are normally found in flouresent fittings, they are there to correct the power factor, in fact they do form a resonant circuit with the inductive ballast. Quote
audioguru Posted September 22, 2005 Report Posted September 22, 2005 Hi Alun,Electricity is cheap over here because it "comes out of the ground" at Niagara Falls. So we don't bother correcting the power factor on little things.Our florescent ballasts are just a big inductor with a filament winding for each end of the tube. They don't use a starter circuit, the tube heats in a second, then it flickers a little and lights. The filaments in the tubes are the 1st thing to fail, then the lamp doesn't light. Near the filaments the glass turns black.Since the filaments waste a lot of power and fail early, these florescent lights are being phased-out, and new ones will use electronics to start the tube, like little compact florescent bulbs do now. ;D Quote
Guest Alun Posted September 22, 2005 Report Posted September 22, 2005 Our florescent ballasts are just a big inductor with a filament winding for each end of the tube. TWhat you've just described isn't just a simple inductor, while this may be the case for small tubes it's impossible for larger ones as the striking voltage even with the fillaments warm is considerably higher than 168V, it's an auto transformer with taps in the coil for the filaments. Quote
audioguru Posted September 22, 2005 Report Posted September 22, 2005 Hi Alun,My tubes are 48" which is about 1.5m. The ballast is just a coil with a couple of filament windings, not an autotransfomer and it works fine on 120VAC. Quote
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