APU Prelim - Incomplete

ELECTRICITY

is the set of physical phenomena associated with the presence and motion of matter that has a property of electric charge.

VOLTAGE

electric potential difference, electric pressure or electric tension is the difference in electric potential between two points, which (in a static electric field) is defined as the work needed per unit of charge to move a test charge between the two points.

CURRENT

is a stream of charged particles, such as electrons or ions, moving through an electrical conductor or space. It is measured as the net rate of flow of electric charge past a region.

RESISTANCE

is a measure of the opposition to current flow in an electrical circuit.

Static electricity

the term static means fixed or at rest that we call it static electricity.

Dynamic electricity

this refers to electrons in motion.

Friction

static electricity

Chemical Action

cells and batteries (primary and secondary cells)

Magnetism

generators and alternators

Heat

thermocouples (junction of two dissimilar metals)

Light

photo electric cell

Pressure

piezo electric crystals

ELECTRIC CIRCUIT

usually consists of voltage source, load and current path. other electric circuits provide some means of control, switches & protection

Fuses and circuit breakers

are used to intentionally create an open circuit when the current exceeds a specified number of amperes due to malfunction condition in a circuit.

Ohm’s Law

is the relationship between voltage, current and resistance and how they relate to each other.