Electricity

Electrical energy, currents, and circuits

1) Electrical energy is the energy of Electric charges.

2)Electric current is the rate at whichcharges pass a given point. (actual flowof electricity)Current is expressed in ampere which isoften shortened by amps.unit for current is ampere (A)symbol for current is I

3)There are two types of currents:DC-direct current(charges always flowsame directionAC-alternating current(charges flowone direction to reverse direction)

4)Voltage is the potential difference between two points in a circuit. This alsodetermines what type of battery you have.

unit for voltage is expressed in voltssymbol is (v)

5)Higher the voltage is the more energy is released per charge. As long asthere is voltage between two points onwire charges will flow in a wire.

The greater voltage is greater the current.

6) Resistance is the opposition to the flow of electric charge.

Unit for resistance is ohms, the Greek letter omega (Ω)symbol is (R)

7)Higher the resistance of the materialLower the current

Resistance depends on thickness, length,and temperature.

conductors have low resistanceinsulators high resistance-this iswhy charges can not flow in them.

8)Cells-device that produces an electriccurrent by converting chemical or radiantenergy into electrical.

Battery-device that produces an electric current by converting chemical energy intoelectrical and is made of several cells.

Two types of cells-dry and wet

9)Ohms law-mathematical formula thatrelates current, voltage, and resistance.

I=V RWhat is the current of an object; if thevoltage is 24V and amps is 2A?I=24V 2AI=12Ω

10)Electrical power is the rate at whichelectrical energy is changed into otherforms of energy.

unit for power=watts(W) or kilowatt(kW)symbol for power=Pformula is power=voltage x current

11)Measuring electrical energy

unit for electrical energy is kilowatt-hours (kWh)symbol=E

formula :Electrical energy=power x time

Electric Circuits Vocabulary:1) electric current 2) Voltage3) resistance4) electric circuit5) load6) series circuit7) parallel circuit

12) The path electricity follows is the circuit, the actual flow of electricity is the current. Two types-series and parallel circuits.Circuits must be closed to work

Items that use electricity are called loads.

13)Circuits need 3 parts in order to work:1) energy source2) wires3) loads

14) Series circuits provide one path or loop for electricity to follow.

15) Parallel circuits provide two or more paths for electricity to follow - different loads are located on separate branches

16) Circuit Symbols