Mutual capacitance is intentional or unintentional capacitance

Capacitance

In electromagnetism and electronics, capacitance is the ability of a capacitor to store energy in an electric field. Capacitance is also a measure of the amount of electric potential energy stored for a given electric potential. A common form of energy storage device is a parallel-plate capacitor...

 that occurs between two charge-holding objects or conductors, in which the current passing through one passes over into the other. Unlike mutual inductance, mutual capacitance only works along short distances. In transmission lines, when conductors are closely spaced together, the air or material separating them acts as a dielectric

Dielectric

A dielectric is an electrical insulator that can be polarized by an applied electric field. When a dielectric is placed in an electric field, electric charges do not flow through the material, as in a conductor, but only slightly shift from their average equilibrium positions causing dielectric...

, and the conductors act as capacitor plates.

All objects in the universe, conducting or non-conducting, that hold charge with respect to another exhibit capacitance. An object's capacitance increases when another object is brought closer to it. The human body is a great charge-holding object (capacitor) (this biological property is called body capacitance

Body capacitance

Body capacitance is a biological property of the human body that makes it a good capacitor and able to store charge. Every person has a characteristic called capacitance. Capacitance is an electronics term that has units of measure called farads. Capacitors are electronic components that store...

), and sensitive capacitive detectors can be made to function as proximity detector

Proximity detector

Proximity detectors are devices that use mutual capacitance between itself and object in order to detect its presence.There are many types of proximity detector. Common types include:# magnetic proximity switch - see reed switch# infrared proximity switch...

s. The capacitive property of the human body is also helpful in making touch switch

Touch switch

A touch switch is a type of switch that only has to be touched by an object to operate. It is used in many lamps and wall switches that have a metal exterior as well as on public computer terminals...

es, such as those used in touch-activated lamps. The lamp constantly charges and discharges its metal exterior, measuring a change in capacitance.

When mutual capacitance occurs adversely (unintentionally) between transmission lines, this is an example of crosstalk.

See also

• capacitive coupling
  Capacitive coupling
  In electronics, capacitive coupling is the transfer of energy within an electrical network by means of the capacitance between circuit nodes. This coupling can have an intentional or accidental effect...
  
  
• capacitance
  Capacitance
  In electromagnetism and electronics, capacitance is the ability of a capacitor to store energy in an electric field. Capacitance is also a measure of the amount of electric potential energy stored for a given electric potential. A common form of energy storage device is a parallel-plate capacitor...
  
  
• capacitor
  Capacitor
  A capacitor is a passive two-terminal electrical component used to store energy in an electric field. The forms of practical capacitors vary widely, but all contain at least two electrical conductors separated by a dielectric ; for example, one common construction consists of metal foils separated...
  
  
• mutual inductance
• inductive coupling
  Inductive coupling
  In electrical engineering, two conductors are referred to as mutual-inductively coupled or magnetically coupled when they are configured such that change in current flow through one wire induces a voltage across the ends of the other wire through electromagnetic induction...
  
  
• crosstalk

External links

• An Intel educational slideshow on crosstalk