How does a touch sensitive lamp work?

Question

A friend of mine recently brought me a touch sensitive light, it's fun to play with but it bugs me that I don't quite understand how it works. My best guess is that by touching the metal part I am interfering with a magnetic field and it's by monitoring that field that the lamp knows if its been touched. Does that sound plausible to the physicists out there? If that isn't right, how does it work?

Answer 1

There's a tiny circuit that controls the switch that would normally control a 3-way light bulb. The lamp body absorbs a tiny amount of charge, like a little battery. When you touch the lamp, the charge transfers to your finger, much like when you feel the spark from a door knob on a dry winter day. The circuit in the lamp is monitoring the amount of charge in body of the lamp, and when you touch it, you change the amount of charge. The charge sensitive monitor "sees" this change and triggers the switch mechanism that controls the amount of electricity going to the bulb.

:)

Answer 2

many different properties of the human body have been used to flip touch-sensitive switches:

* Temperature - The human body is generally warmer than the surrounding air. Many elevators therefore use buttons that are sensitive to the warmth of the human finger. These buttons, of course, don't work if you have cold hands. The motion-sensitive lamps you see on people's patios also sense the heat of the human body.

* Resistance - The human body, being made mostly of water, conducts electricity fairly well. By placing two contacts very close together, your finger can close the circuit when you touch it.

* Radio reception - You may have noticed that, when you touch an antenna, the reception gets better on a TV or radio. That's because the human body makes a pretty good antenna. There are even small LCD TVs that have a conductive neck strap so that the user acts as the antenna! Some touch-sensitive switch designs simply look for a change in radio-wave reception that occurs when the switch is touched.

Answer 3

This Site Might Help You.

RE:
How does a touch sensitive lamp work?
A friend of mine recently brought me a touch sensitive light, it's fun to play with but it bugs me that I don't quite understand how it works. My best guess is that by touching the metal part I am interfering with a magnetic field and it's by monitoring that field that the lamp knows...

Answer 4

You cause a partial earth disturbance as the wiring.
Sometimes it doesn't work as it should because the unit inside is cheap and always not serviceable
Then you have to dissasemble it remove the resistor thingy and get it to work as normal lamps do.
I once had one as a bedside lamp and the bl**dy thing would come on in the night as I was flailing around - as you do.
Any way what are servants for?

Answer 5

Anthony is right. It works like an RCB (Residual Circuit Breaker). Touching the lamp creates an imbalance in the circuit which 'tells' the switch to become live.

Answer 6

Great question!

I have two of these lamps in my lounge and it never occurred to me to wonder how they worked!

After reading the submissions here I think that it is the touch that completes the electrical circuit...course I could be wrong...it COULD be magic!!

;7]

Answer 7

The body acts as a conductor. By thouching the metal lamp, you are creating a full cirtcut letting the electricity flow, therefore turning the lamp on.

Either that or it just senses the heat from your body and says
"Oh! It want me to give him light!"
Of course it isnt saying it, but you know what I mean.

Answer 8

I always thought they worked due to hand capacitance, in a simple home made radio, if you put your hand near the tuning coil the radio will whistle
PS I'm talking about old fashioned valves, I don't know if transistors work the same.

Answer 9

Just touch the lamp and enjoy the light leave the mechanics to the manufactories

Answer 10

Simple. Your finger completes the electrical circuit. Just like in any other lamp.

Or maybe it's magic. I don't know.