Electrical Symbols & series vs parrallel Cirtcuts and formulas

Symbos and current, voltage, resistance in series and parallel

Cell

Battery of cells

Power Supply

d.c Power supply

a.c power supply

Fixed resistor

Variable Resistor

Heater

Fuse

Switch

Earth or ground

Junction or conductors

Lamp

Generator

Motor

Ammeter

Voltmeter

Light-emiting diode

Electric bell

Series Circuts

A series circuit is a circuit in which components are arranged in a single path.

Current in a series circut

• The current is the same through each component in a series circuit.

• I=I1=I2

Resistance in a series circut

• The total resistance in a series circuit is the sum of all individual resistances: Rtotal= R1 + R2 +R3

Voltage in series circut

The sum of the voltage drops across each component is equal to the total voltage supplied by the source.

• Vtotal=V1+V2+V3

Parallel Circuts

A parallel circuit is a circuit in which the components are arranged so that there is more than one path for the current.

current in a parallel circuts

I=I1+I2

Resistance in a parallel circut

Voltage in a parrallel circut

V=V1=V2

Charges: positve and negative

positive + positve= repel

negative + negative= repel

Electrical conductors and insulators

Conductors: The process of electrical current flowing through a wire is called conduction

.silver

.alluminium

.graphite

Insulators: Most non-metals do not allow electrical current to flow through them easily.

rubber

plastic

.glass

Electrical Charge

a fundamental property of matter that causes it to experience a force in an electric field.

Is meaured in coulombs (C)

Calculating Charge

Charge=current x time

What measures current

Ammeters

Electrical Current

is a flow of electric charge.

Measued with a...

Ammeter

In metals the charge is related to

the flow of electrons

The difference between a a.c and a d.c current (alternating and directs current)

d.c an electrical current that flows only in one direction

a.c= an electrical current that changes direction at regular intervals

Calculating current

-Current=Charge/Time

or

-I=Q/T

Potential difference=

voltage

definition

The p.d is the work done by a unit charge passing through a component

mesuring potential difference

use a voltmeter

voltmerers are always connected in parallel

Electromotive force

Is the electrical work done by a source in moving a unit of charge around in a complete circuit

is measured in volts

Voltage is shared between...

the components in a series circut

Resistance= (ohms law)

Resistance=Voltage/Current (R=V/I)

Current Voltage/Resistance

Voltage Current X Resistance (V=IxR)

Resistance is...

directly proportional to length an indirectly proportional to the cross_sectional area

Electrical Circuts transfer..

electrical energy (like electrical cell or main supply) to the circut components

Electrical Power

Power=the rate at which energy is transfered

Calculating Electrical Power

power = Current x voltage (P=I x V)

power is mesaured in Watts

Electrical energy

The energy of electric charges

Calculating electrical energy

Electrical energy current x voltage x time (E=IxVxT). Energy is measured in joules

Kilowatt-hour (Kwh) is a unit of

energy

Formula for Kilowatt-hour

energy=powe (kilowatt) r x time (hours)