Transcript 9 Electrical symbols

EGD
ELECTRICAL
ELECTRICAL
SYMBOLS
Distribution board
• This board houses all the trip
switches for the various circuits as
well as the earth leakage relay or
unit.
• It can also house other units such
as timers or even an electricity
meter.
Earth
• Used together with Earth leakage
unit.
• This unit detects a leakage of
electricity down to earth.
One way switch
single pole
One way switch
Double pole
One way switch
Three poles
Two way switch
Regulating switch
e.g. dimmer
SWITCHES
This device comes in various
shapes and is used to break the
flow of current in a circuit
Socket outlet
Switched socket outlet
Allows the user to plug in different electrical
appliances.
Fluorescent lights
3
x
40W
Lights – Bulb type
Lights – wall mounted
• Light types include bulbs and tubes.
• Energy efficient lighting uses less
electricity.
• BULB: A bulb lights up when current flows
through it, and is not polarised.
Light Emitting Diode
Light Emitting Diode or LED
• It lights up when current flows
through it,
• but is polarised, and will not work if
connected incorrectly.
AMPERE AND VOLT
METERS
A
V
AMPERE (A) This unit is used to
measure the amount of current flowing
in a circuit
• Every appliance connected to a circuit
will draw a certain amount of current
when in operation.
VOLT (V) This unit is used to measure
electrical pressure.
• The single phase voltage used in SA for
domestic use is 220 Volts
CELLS AND BATTERIES
• A cell is a single unit.
• Two or more cells, connected
together creates a battery.
Mains switch (Industrial)
• Mains switch controls the power
supply to the distribution board.
• Mains switch controls the supply
inside the distribution board, to all
the different circuit breakers inside
the distribution board.
Fuse
This device is used to break the flow
of electricity whenever a circuit is
overloaded.
• This device is used as part of
protection for electrical devices.
• Must be replaced when blown.
Circuit breaker
• Performs the same function as a
fuse.
• When the switch trip, it only needs
to be reset and not replaced.
Single pole single throw
Single pole, double throw
• This device comes in various
shapes and sizes
• This device is used to break the
flow of current in an electrical
circuit.
Push to make switch
Push to break switch
• PUSH TO MAKE SWITCH,
• release to break switch.
• NO (normally open circuit)
• PUSH TO BREAK SWITCH,
• release to make switch.
• NC (normally close circuit)
Symbol for ON / OFF
Resistors
• A resistor limits the amount of
current flow in a circuit.
• These values are indicated by a
series of coloured bands on them
Power supply types
• AC is the abbreviation for
alternating current.
• AC is the electricity supplied to our
homes and industry
• DC is the abbreviation for direct
current.
• DC is the type of electricity
supplied by a cell or battery.
Buzzers and bells
• A buzzer or a bell converts
electrical current into a sound
wave.
• Can be used as a warning
indicator
Transformer
• A transformer consist of coils, using
the magnetic field created by the
flow of the electricity input on the
primary side.
• It is use to step up (rise) or step
down (lower) the supply of electricity
on the secondary side.
• Can only be used with AC cycle.
CapacitorElectrolytic or non electrolytic
• It is use to store electrical current
• and the capacitor will then supply
the stored current when needed.
Motor
M
• A motor uses electromagnetism to
produce movement when the motor
is connected to electricity.
• In DC motors, if the polarity is
changed, the motor will rotate in the
opposite direction.
Geysers
G
• Provides hot water.
• Water is heated by means of a
thermostat regulated element.
Aerials
• Different types of aerials can be
used for sending and receiving of
radio waves and signals.
ELECTRICAL
CIRCUIT
(1)