Do electronics really need power?

It was hard for me to place this question under a specific topic, but eventually chose science because it dealt with power...

Scientists estimate that 90% of the universe's power remains undiscovered. Is it possible then that everyday technology does not really need power at all? I only ask this because of a peculiar event that happened a few months ago.

I had been cleaning my room one day, it had gotten really messy, when my brother walks in and turns on the electric keyboard, Casio CTK-651, and played a few notes then walks out but leaves the keyboard on. I had been sitting on my bed when I look over and see something had been unplugged. I didn't know what it was, since I don't typically leave things unplugged in my room, then I said to myself "No way". I turn off the piano and try to turn it back on, but it won't. That means the keyboard was working and it wasn't even plugged in. Neither of us knew what it meant, or how it could keep working.

Before you ask, it does take batteries, but it requires so many I've never bothered putting any in.

Is it possible that the keyboard was operating under some sort of alternate power. Basically, all I want to know is, how did this happen and has anything similar happened to anyone else?

Originally posted by MrJingles
I turn off the piano and try to turn it back on, but it won't. That means the keyboard was working and it wasn't even plugged in.

The only thing that means it wasn't plugged in is that you checked the cord and saw that it wasn't plugged in and he didn't unplug it when he was done.

It happens to me all the time, with remotes. I dont really need batteries half the time. It saves alot of money I can say that!! I normally affect electrical stuff though, so Ive grown to get used to it.

Nearly all electronics contain capacitors, often used to filter out high frequency noise on power sources. Capacitors will store low frequency current (12 VDC for example) while allowing high frequency current to pass as if the cap were just a wire.

Your keyboard for instance, is taking the 110VAC from the wall, dropping it down to probably 24 or 12V and then rectifying it to a DC signal, instead of AC. There would then be a filter capacitor in place between the positive and ground leads to let any excess noise from the 60Hz AC be drained away so it doesnt enter the circuitry.

Once a device containing such filter capacitors is unplugged or powered off, the caps will usually drain a little bit of stored power back into the system until discharged. It wouldn't be enough to actually run your keyboard, but enough to keep a few LEDs lit for a short amount of time.

> I hope I follow what the issue was... the stuff with the cords got me all confizzled so I think this is what you were talking about. Otherwise uhm... you just didnt notice it was plugged in before... ?



[edit on 22-7-2005 by apc]

Basically what happened, I guess I wasn't clear before, was the piano wasn't plugged in. It had been turned on while it was unplugged. I saw this then turned off the piano, at which point I tried to turn on the piano again and it wouldn't because it was unplugged. I tried to turn the piano on again just as a simple test to see if that was the plug for the piano.

was there a battery in the keyboard?

I've had several electronics work without being plugged in. In most cases, there was a lightning storm going on and certain things worked: tv, lamp etc... But other times I thought that it must have just been an electrical build-up or charge.

[edit on 22-7-2005 by puppet]

Originally posted by MrJingles
I had been cleaning my room one day, it had gotten really messy, when my brother walks in and turns on the electric keyboard, Casio CTK-651, and played a few notes then walks out but leaves the keyboard on. I had been sitting on my bed when I look over and see something had been unplugged. I didn't know what it was, since I don't typically leave things unplugged in my room, then I said to myself "No way". I turn off the piano and try to turn it back on, but it won't. That means the keyboard was working and it wasn't even plugged in. Neither of us knew what it meant, or how it could keep working.

This remind of Nicholas tesla inventions...

I would not be surprise if that's what happened exactly.

I have a high power speaker which I unplug the night before. On the next day, without plugging it, I turn on the power button...it did get On for short time and then fade away....

I think that the keyboard, like my power speaker stores a small amount of electricity within the circuit...

when your brother turn the keyboard on, was it for a short time?

Originally posted by mwen
I have a high power speaker which I unplug the night before. On the next day, without plugging it, I turn on the power button...it did get On for short time and then fade away....

This is capacitor discharge as I described. Perfectly normal operation.

MrJingles: just sounds like your brother unplugged it without you noticing. I assume when you say you saw it turned on, you mean you saw the power LED still lit. It was just being kept alive by a capacitor. Nothing really abnormal. By flipping the power switch you effectively drained the remaining charge so when you turned it back on there was nothing left to power the LED.




[edit on 23-7-2005 by apc]

Food enters mouth, digested, then goes on to become amino acid to make protein, muscle, make you strong. Yes, power is necessary for everything. Cannot imagine what one thing in the universe that does not need power to operate.

Your piano will not play if you do not press down on the keys.