The term polarity describes the addition or arrangement of two poles (opposite extreme points) in space.
This can be, for example:
- Poles of an electrical potential difference ( electrical voltage , for example a battery )
- the alignment of the two areas on a magnet, in the vicinity of which the magnetic field strength is particularly high, see magnetism
- Anode and cathode of a diode and their position during installation
- Connections of an AC voltage source in relation to its phase position (inverted or not inverted)
The polarization indicates the formation of opposite charges in a in this context insulating -body due to an inhomogeneous distribution of charge. The direction of polarization ( transverse waves , antennas , electromagnetic waves , light), on the other hand, only has something to do indirectly with polarity.
Molecules are polar if they have different centers of charge of their positive and negative charges, see polarity (chemistry) .
- Further examples
If the two a / b wires of an analog telephone connection are reversed in polarity in b / a , a simple telephone will still work, although DC voltage (60 V) is applied to the telephone connection. The polarity or polarity is - as with AC - consumers the power grid - not matter.
In contrast, the polarity is mandatory or important in the following cases:
- Series connection of transformer windings (alternating voltage in antiphase or in phase)
- Assignment of the three outer conductors for three-phase current (determines the direction of rotation)
- Polarity or polarity of a diode ; see also rectifier , freewheeling diode
- Polarity of an electrolytic capacitor
- Polarity of a battery (motor vehicle, battery-operated devices)