Electrical resistance
principle · 1827 · Industrial Revolution
A conductor opposes current; Ohm’s law relates current and voltage.
Principles and materials it uses
- Electrical conduction — uses. Resistance is a property of a conductor.
Where it is used
- Joule heating — is used in. The heat released depends on the conductor’s resistance and the current.
- Electric motor — is used in. The resistance of the windings determines the losses in a motor.
- Electric arc — is used in. The discharge carries current through an ionized gas.
- Power line — is used in. High voltage reduces resistive losses.
- Resistor — is used in. Sets a resistance.
- Rheostat — is used in. More resistance means less current at the same voltage: that is how a rheostat controls the current.
- Multimeter — is used in. Measuring resistance.
- Potentiometer — is used in. A voltage divider.
- Strain gauge — is used in. Resistance changes under strain.
- Photoresistor — is used in. Light changes the resistance.
- Thermistor — is used in. The resistance depends on temperature.
- Varistor — is used in. The resistance drops at high voltage.