STRANGE LED behavior...

Just got the new Nichias--great little LED's!

Was testing one hooked up to a 9v bat with a 100 ohm resistor.
I turned out the light, and was fumbling to make the connection to see how bright it would be compared to an ARC aa.

Well, I was holding onto the - lead from the LED between my left thumb and index finger, and my left pinky touched the - terminal of the bat...and the LED lit up! It was dim, perhaps 1/100 ma, but it lit up!

I showed my wife, and she wanted to try it. She grabbed the - bat terminal with her left hand, and held the - LED lead with her right hand...same thing, it lit up!

I had no idea that current could flow so far through the human body with such little voltage.

Anyone ele have this happen???

Bob

I am not sure what really happened but try doing it with other types of LEDs some doesn't even glow. The Nichia glows nicely.

-vince.

It is not strange. With a 9 Volt battery, you can drive more than 0.2 mA into the LED if you wet two fingers of one hand.
Dry fingers will drive 0.01 to 0.05 mA into the LED, that will be glowing.
This happens not only with Nichias but with any LED. The "trick" is to have enough voltage.

Anthony

In a dark room I've had barely visible glow from some LEDs at a drive current of 50 µA, and enough light to get around with once my eyes were dark adjusted at maybe 100 µA. The human body has resistance in the tens of kiloohms, so a 9V battery will cause some tenths of a mA to flow (more with wet fingers), more than sufficient to give visible glow to many LEDs.

Bob, it should be comforting to know that you and your wife are properly polarized and mutually conductive. Hopefully, that's a sign of good health. /ubbthreads/images/graemlins/grin.gif

I once had a toy, consisting of a ping-pong ball, a 3mm LED with a stack of button cells inside and two contact strips on the outside.

If you put the ball on your hand so that both contact strips had contact with the skin, the LED lit up and made the ball glooooooowwwwww.

Really nice effect, especially if you hold the ball to hide the contacts.