ELECTRICAL CIRCUITS

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ELECTRICAL CIRCUITS

MEASUREMENTS

CURRENT

flow of electrons

measured by: ammeter

units: ampere(A)

POWER

definition: energy used per second

units: watts(W)

VOLTAGE

measured by: voltmeter

connected in parallel

units: volts(V)

components

DIODE

current only flows when voltage is greater than 0.6v

BULB

curve

RESISTOR

straight line

series - parallel current: all components are connected end to end to form only one path for the current to flow through the circuit.

For example: multiple bulbs are connected with wire and also some are in the loop

used for: voltage dividers

parallel circuit: it is a circuit that comprises branches that the current divides and only part of it flows through any branch.

example: light fixtures that use multiple bulbs.

used for: to keep electricity flowing when one pathway is interrupted.

series circuit: it is a circuit comprises a path along which the whole current flows through each component.

examples: often lawnmowers have two switches in series with each other so both need to switch before the mower will turn on.

used for: it provides exactly one path between any two points for electric current.

TYPES

series parallel circuit

PARALLEL CIRCUIT

SERIES CIRCUIT

LAWS OF ELECTRIC CIRCUIT:

KVL LAW

ENTERING CURRENT AT NODE IS EQUAL TO LEAVING CURRENT AT NODE.

KCL LAW

THE ALGEBRAIC SUM OF VOLTAGE AT NODE IN A CLOSED CIRCUIT IS ZERO.

OHMS LAW

CURRENT THROUGH A CIRCUIT IS PROPORTIONAL TO THE VOLTAGE ACROSS THE CONDUCTOR

KIRCHHOFS LAW

RESIDUAL CURRENT DEVICE: compares current in live and neutral wires. used in gardens.

MINIATURE CIRCUIT BREAKER: it replaces fuses. electromagnets used in it. melts if the current is too big.

no protection against electric shock.

FUSE: melts if current is too big

no protection against electric shock

EARTH LEAD: current directly flows straight to earth.

protects against electric shocks

PLUG

INSULATION

black

NEUTRAL

blue

EARTH

green and yellow

LIVE

fuse

brown

Example: battery, lamps, generators, and so on.

it can be defined as the path for transmitting electric current.