Electricity.

a Form of Energy & Light.

Electric Charge.

Basic component of Electricity is Electric Charge.

Electric charge in normal state of physical body is neutral. In isolators this state can be changed, for example by rubbing.

Electric charges affect each other with force (for example, when two rods of acrylic glass or ebonite are near each other).

Charges with the same polarity are repelling each other, while charges with the opposite polarity are drawing each other near.

Electric charge is measured in ampere-seconds (A·s) also called Coulombs (C).

Electric charge depends on amount of electrons orbiting around nucleus, as well as on amount of protons in nucleus.

More electrons make for negative polarity, more protons for positive polarity.

Atom with non-zero charge is called 'ion'.

Elementary charge, minimal possible amount of charge in electron or proton is either: -1,602 x 10^-19 C, or +1,602 x 10^-19 C respectively.


Voltage.

Between opposite polarity charges there's force of attraction.

If needed to separate charges, work is neccessary against forces of attraction.

Work becomes stored as potential energy, between charges voltage is made.

There's inclination for charges to neutralize themselves, so electric voltage is also inclined to neutralize itself as well.

Electric voltage is force used to separate charges, in comparison to charge's magnitude.

Electric voltage (symbol: U) is measured by voltmeter.

Unit of voltage is volt, which has symbol of V.

V: [U] = 1V.

Electric Charge.	Voltage.
[Q] = A · s = C	[U] = N·m / A·s = J / C = V (read: unit of voltage is volt).
Q = I · t Q is electric charge, I is electric intensity, t is time	U = W / Q U is voltage, W is work, Q is electric charge.

Voltage can be considered as the electric pressure. If two metallic bodies with opposite charges are connected by a conductor, electrons move caused by the voltage from negative electrode to the positive electrode.


Voltage relative to certain point, for example on ground is called 'potential'. Voltage can be presented as difference between two potentials.


Current.

Presence of voltage causes electric current flow.

Electric current can flow only in closed circuit.

Electric circuit consist of source, destination & wires (in any form) connecting source to destination.

Electric circuit can be opened or closed with electric switch.




Electric Circuit.

Materials contain electrons, which may move freely within material. These electrons are called 'free electrons'.

Free electrons move from places where there are too many electrons to places where is not enough of electrons.

In proper conductors, for example: in copper or silver, there are almost as many free electrons as there are electrons moving on atoms' external orbits.


Directed electrons flow we call: 'electric current'.


There's force in electric current, that affects free electrons. That force affects whole electric circuit after it's closed.

Electrons move affected by that force.

Direction of the electric current is opposite to the electrons flow & equal to the flow of positive ions in fluids.


Electric current affects surroundings in various ways.

Heat & magnetism occurs all the time. Light, chemical affects, living organisms affects occur only in certain conditions.

Electric current (symbol I) is measured with ammeter.

Unit of current's intensity is ampere (A).

There's:
- Direct Current (DC) - direction of electrons flow is constant, from negative pole to positive pole,
- Alternating Current (AC) - direction of electrons flow alternates constantly,
- Universal Current (UC) - consists both of AC & DC.


Difference betweeen Amperage & Voltage.

Amperage, or current, is a measure of the amount of electrons moving in a circuit.

Voltage is a measure of how much force those electrons are under.