Physics - electricity & semiconductors

Conductor

Substance trough which electric current can flow

Insulator

Substance trough which electric current can't flow

Direct Current (DC)

Electric current that flows in only one direction

Alternating Current (AC)

Electric current that reverses direction periodically

Coloumb's Law

The force of attraction or repulsion between two point charges is directly proportional to the product of the charge and inversely proportional to the square distance between them

Electric field

Any region of space where the static electric charge experiences a force other than the force of gravity

Caused by other static charges in the vicinity

Electric field strength

Force per unit charge

potential difference

Between two points in an electric field is the work done to bring +1C from one point to another (V)

Capacitance

Ratio of charge on a conductor to its potential

Size of an electric current

Is the amount of charge passing any point of that conductor per second

Q=It

charge = current x time

Ampere

Coulomb per second

EMF (electromotive force)

voltage when applied to a circuit

Resistance

Of a conductor is the ratio of potential difference across it to current flowing trough it

Joule's law

Rate at which heat is produced in a conductor is directly proportional to the square of the current flowing trough it -provided that resistance is constant-

Fuse

Piece of wire that melts when current of a certain size passes trough it (safety measure)

Semiconductor

A substance whose resistivity is between that of a good conductor and a good insulator

Intrinsic conduction

The movement of charges through a pure semiconductor.

Extrinsic conduction

The movement of charges through a doped semiconductor.

Doping

The adding of small controlled amounts of another element to a pure semiconductor to increase its conductivity

n-type semiconductors

Semiconductor in which electrons are the majority of charge carriers

p-type semiconductor

Semiconductor in which holes are the majority charge carriers

p-n junction

Piece of semiconductor with a part of it doped p type and the other part doped n type

Depletion Layer

Region at the p-n junction that contains no free charge carriers so behaves as an insulator

Junction voltage

Is the potential difference that exists across a p-n junction caused by holes and electrons moving across the junction when it was formed (a foce is necessary to move charge, creates potential difference, so voltage)

Rectification

conversion of AC to DC

Ohm's Law

The current flowing trough a conductor is directly proportional to the potential difference across it, assuming constant temperature

Current

Measure of the rate of change of the flow of charge