When a TV is in standby, there is a current flowing to keep the cathode filament hot so that when you turn the TV on the picture comes up immediately. In fact, almost all AC-powered electronics have some current flowing even when they’re “off”, since the transformers draw some current just from being connected to the line. This is called the excitation or magnetizing current and represents an iron, or core, loss. Unless the device has a switch that interrupts the main before the transformer, this excitation current will continue to draw power.
I should also point out that TV standby power is only on the order of a few watts, and not worth worrying over, unless electricity is extremely expensive where you are. Go on and make him happy by leaving it on standby.
Well, you certainly don’t want to unplug your appliances, or else electricity will leak out of the sockets (per James Thurber’s aunt).
However
If you are using a dimmer switch ,which the op isn’t ,it draws current constantly as long as it is turned on. Weather the light bulb is burned out or not.
The real problem is the heat. Thats what melts the wax inside the lamp. It is trapped so the bulb stays hotter than it is ment to be.
Hey Alice
Try an appliance bulb.they are made to handle more heat.
Wax? What wax? Ordinary bulbs fail because the tungsten evaporates off the filament, eventually making it too thin to handle the current through it, and it fuses. Appliance bulbs fail in exactly the same way, and wouldn’t last any longer in a standard fixture.
What wax? Try an appliance bulb? From the OPer:
(And yes, I know that polyethylene glycol isn’t really “wax”)
Ah, that wax. For some reason I read that as wax inside the lightbulb.
So there is no solution to my burning out bulb then?
I alwasy thought it was the turning on and turning off that made the blub burn out - however, I don’t turn the lamp on and off - I just leave it on for that wacky, retro feel.
The bulbs will last about 3 weeks and then they die. Am I doing something wrong, or is it the heat that’s making the lava flow that’s also doing in the bulb?
There were some devices marketed a while back that claimed they could extend bulb life by rectifying the AC into DC, but I can’t find them now, and I don’t think they actually worked, in any case.
When the filimant breaks, you still have the two metal posts that held the filimant. These make a VERY small capacitor*. At 60 (or 50) Hz, I’m guessing the current is negligable.**
- assume free space, area of 1mm^2, distance of 1cm
8.85 * 10^-12 *10^-6 / 10^-1 = 88.5 * 10^-18 Farads
** impedance is 1/jwc. w=377 , = 29.97 * 10^12 Ohms
For a power draw (V^2/R) of 480 * 10^-12 Watts
Brian
(who probably made a math mistake)
Of course, I neglected the inductance in the metal posts, but that is very small also. You have to worry about this stuff at GHz frequencies, but not at 60Hz.
Brian
A capacitor[sup]1[/sup] doesn’t dissipate[sup]2[/sup] power.
[sup]1[/sup] [sub]An ideal one, at least.[/sub]
[sup]2[/sup] [sub]It only stores and releases energy.[/sub]
I don’t think so. Having the CRT filament on 24/7 would shorten it’s useful life considerably and use more power than necessary. I believe only the IR remote receiver is powered in standby. My TV takes a few seconds to warm up and show the picture.
In reality, and for these purposes, there is no power draw in an open circuit. A burned out bulb is an open circuit. With no measurable path for the electrons to flow there will not be a reflection on your meter or electric bill.
At 60 hertz and 120 volts there just isn`t enough there to push a measureable amount of current across the typical open ciruit. This system could be argued to have some leakage, but not enough to make any difference in safety or as far as energy savings goes.
Other types of bulbs that require a ballast for their operation will draw some power even if they have an open filament. The transformer in the ballast will always use some energy unless the switch is turned off.
[quote]
The monitors have three power states: OFF, STANDBY, and ON. In the OFF state, there is no power on the monitor, the CRT filament is cold, the screen is dark, and the unit will not respond to remote commands. In the STANDBY state, theunit is powered up, the CRT filament is warm, the screen is dark, and the unit will respond to remote commands.]From This PDF document. I was wrong about the filament beign kept hot nowadays, it is only kept warm, although some older televisions did do so. Also, I should note that this doesn’t apply to all televisions.
Q.E.D. I believe that is talking about computer-type monitors which are expected to have faster response and i even doubt all of them keep the filament warm I doubt TV sets do that though as they are not expected to respond as fast as when you return to your desk.
So, ignoring all this fascinating information for just a moment - does anyone have suggestions for making my lava-lamp bulb last longer?
Just checking.
I’ve read cites that indicate that you can increase bulb life by 4 times, by running it at 75% rated power using a dimmer. Worth looking into, perhaps. I seem to recall seeing plug-in dimmers for table and floor lamps and the like.
I have not yet figured out how to quote, but up there Desmostylus said
“Fluorescence refers to a process of absorbing e-m radiation of one frequency, say UV, and re-emitting another frequency, usually visible.”
I don’t know what they teach physicists or engineers but we chemists are taught that flourescence is the process where a molecule or atom moves from a higher singlet state to a lower singlet state by resleasing a photon. Technically I guess you could go from a higher triplet state to a lower triplet state, but the point is it does not matter to a chemist how the molecule got to the higher state, when it releases that quantum of light, it is called flourescence.