ELECTRIC CURRENT Electric current is the net movement

ELECTRIC CURRENT

Electric current is the net movement of electric charges in a single direction. A spark from your finger tip to a door knob. Lightening from a cloud to the ground. Electric current is measured in amperes or amps. Unlike a spark or lightening electric current is a continual flow of electrons. 1 ampere is equal to 6. 25 x 10¹⁸ or million billion electrons passing a point every second.

There similarities between the flow of water through a pipe and the flow of electricity through a circuit. The pressure of the water flowing through the pipes on this slide compare to the voltage (electric potential) flowing through the wires of the circuit. The unit used to measure voltage is volts (V).

Voltage difference is related to the force that causes electric charges to flow. Voltage difference is measured in volts. The movement of an electron in an electric circuit is caused by an electric force acting on the charges An analogy: Water flows from high pressure to low pressure, electric charges flow the same basic way from high voltage to low voltage, this is the voltage difference the severity of the difference between the high and the low.

What are batteries? Batteries are composed of a chemical substance which can generate voltage which can be used in a circuit. There are two kinds of batteries: dry cell and wet cell batteries. Below is an example of a dry cell. The zinc container of the dry cell contains a moist chemical paste surrounding a carbon rod suspended in the middle.

Wet cell A wet cell battery has a liquid electrolyte. Other names are flooded cell since the liquid covers all internal parts, or vented cell since gases produced during operation can escape to the air

What is electrical resistance? Resistance (R)is the opposition to the flow of an electric current, causing the electrical energy to be converted to thermal energy or light. The metal which makes up a light bulb filament or stovetop eye has a high electrical resistance. This causes light and heat to be given off.

The unit for measuring resistance is the ohm (Ω). Resistance is the tendency of a material to oppose the flow of electrons.

Material can be labeled conductors and insulators with regard to the tendencies to allow electrons to flow or not to flow. Copper allows electrons to flow easily and is considered a good conductor of electricity. Rubber does not allow electrons to flow easily and is considered an insulator. Temperature, Length and Thickness When the temperature of the material goes up the resistance of the material usually goes up. The longer the wire is the greater its resistance The thinner the wire is the greater the resistance

What are electric circuits? An electronic circuit is a closed path or paths formed by the interconnection of electronic components through which an electric current can flow. Circuits typically contain a voltage source, a wire conductor, and one or more devices which use the electrical energy.

In electrical circuits, Ohm's law states that the current through a conductor between two points is directly proportional to the potential difference or voltage across the two points, and inversely proportional to the resistance between them. Current(in ampere) = Voltage difference (in Volts) resistance (in ohms) I = V/R Or written R= V/I