How do touch-sensitive lamps work?
Switches that are sensitive to human touch — as opposed to switches that must be flipped or pushed to make and break a mechanical connection — have been around for many years. They certainly have advantages, and the most important is the fact that dirt and moisture cannot get into the switch to gum it up or damage it. Over the years, 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
Switches that are sensitive to human touch — as opposed to switches that must be flipped or pushed to make and break a mechanical connection — have been around for many years. They certainly have advantages, and the most important is the fact that dirt and moisture cannot get into the switch to gum it up or damage it. Over the years, 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
Switches that are sensitive to human touch — as opposed to switches that must be flipped or pushed to make and break a mechanical connection — have been around for many years. They certainly have advantages, and the most important is the fact that dirt and moisture cannot get into the switch to gum it up or damage it. Over the years, 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
