Current, Voltage, Resistance

Atom

Protons

Neutrons

Electrons

Electrical Charge: When there are fewer electrons than protons, the charge is positive. The unit of electrical
charge is the coulomb (symbol: C).

Electrical charge: When an atom loses or gains an electron

Electrical Current

Current: The movement of negative electrical charges (electrons)
through a conductor (electrical wire, metal foil, etc.).

Amperes: The number of electrons that pass a point in a circuit in one second

Circuit: Electric current flows through a closed, continuous path.

It is made up of a series of electrical components and conductors (e.g., batteries, electrical wires, light bulbs, etc.)

Conductors

bodies or materials that allow an electrical
current to pass through them. (Examples: Copper, aluminum, brass, zinc, iron, pewter, and salt water.

Insulators

Materials that do not easily transmit heat, cold, or electricity, such as wood and plastic. Electrical wires are covered with an insulator to prevent electrical shocks and short circuits that could cause fires.

Short Circuit: Occurs when two current-carrying conductors accidentally come into contact, either directly or through a conducting object.

Voltage: is the difference in electrical potential between two points where electrons are flowing

Electric Potential

The amount of potential energy per charge

Voltage is the “push” that makes electric charges flow, measured in Volts (V)

Batteries: Electron pumps

Batteries are reserves of chemical
energy that can be transformed into
electrical energy

They provide an energy source to a
circuit

Resistance: The part of an electrical circuit that resists the flow of electricity (for example, by
transforming it into heat or light, as in a light bulb or a buzzer).

Measured in ohms (Symbol is Greek letter omega Ω)

Electrical Charge: When there are
more electrons than protons, the charge is
negative.

Types: wet-cells & dry-cells

Types Of current

Direct Current

current that flow in the same direction in a circuit (DC)

Alternating current

current that alternates its direction many times a second a regular intervals
in a circuit (AC)

Typically used in power supplies.

House outlets use 120V AC

Transformers change AC to DC