Physics Question #308
Edward Driedger, a 11 year old male from the Internet asks on December 17, 1997,
How do touch lamps work? If one person touches the touch pad and someone else taps his other hand, will the light still react?
viewed 13588 times
answered on December 17, 1997
Most touch lamps work using a capacitive sensor. The dielectric field strength changes when a foreign object is brought in proximity with the switch. The capacitance is altered according to C = e*A/d where e is the dielectric, A is the cross-sectional area of the capacitor plates and d is the distance between plates.
The reason why a second person can touch the first person to make the switch work is because this, too, changes the dielectric field strength enough to actuate the switch.
Add to or comment on this answer using the form below.
Note: All submissions are moderated prior to posting.
If you found this answer useful, please consider making a small donation to science.ca.