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Description |
Symbol |
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Fixed carbon film
resistor, the same symbol is use for surface mounted fixed
resistors.
All are available in a
range of values 1ohm - 10 mega ohms, use a colour code table to
select the value required. |
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Potentiometer - variable
resistor, comes in various package types but use the same
symbol
Available in a range of
values they come with linear or logarithmic tracks.
Typical uses include volume controls and for any circuit that
might require regular adjustment. |
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Preset Potentiometer,
usually surface mounted they have two package types.
Available in a range of
values. Typical uses include circuits that require initial setting
up and fine tuning, these are not designed for regular
adjustment. |
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LDR (Light Dependent
Resistor).
A semiconductor which
varies its electrical resistance dependent on light level. ranging
from 150 Ohms in daylight to 10 M Ohms in the dark.
Typical applications
include outdoor lighting, light dependent counting
systems. |
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Miniature disc
thermistor similar to the LDR above but changes with heat instead of
light.
Its resistance falls with
temperature increase. used in alarm systems and other application
where warning of temperature change is needed.
They come in a range of
temperature to resistance types. |
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Standard type micro
switch.
It employs a lever arm
for operation different lengths of arm are available. Each
switch has three terminals Normally open and Normally
closed This makes them useful for both press to make and press
to break applications.
Typical applications
include starting or stopping a motor on contact, used in safety
guards on machinery etc. |
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Slide Switch, used in
many radio's to change bands AM to FM for example.
This symbol shown is a
Double Throw Double Pole type it has two positions. The middle
connects to one or the other outer pair.
Common in
older radio's it is still used for a range of switching
application even today, often disguised behind a
plastic cap on the outer surface of equipment.
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Rotary Switch.
The switch is
available in various forms including PCB mounting.
The switch can
have multi-pole configurations typically 1 pole 12 way, 2
pole 6 way, 3 pole 4 way or 4 pole 3 way, it can also come ganged
together to create larger switches. |
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A small Press Switch
used for a variety of applications.
It is a non latching
switch which is available in Press to Make and Press to Break
types. |
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A d.i.l. dual in line
switch.
This example contains 8
individual switches (SPST) many variations are available. The
dimensions of the switch make it suitable for PCB mounting or d.i.l.
socket mounting.
Used in many applications
for circuit configurations, Typically in personal
computers & Printer etc. |
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Basic Toggle Switch
which has a million and one uses.
This example is a single
throw single pole switch but they come in many types and with
varying current ratings also available SPDT, DPDT, they can
also be biased, self-centring or latching types.
Used as a power switch in
many applications. |
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Tilt Switch.
These usually contain
mercury which bridges a contact between two poles when it
rolls to one end. non mercury types are available, more
environmentally friendly than its mercury predecessor.
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Electrical
Buzzer.
A wide variety of buzzers
are available this being a typical inexpensive one.
Applications include
warning devices, burglar alarms, etc. |
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Electrolytic
Capacitor.
This example is a radial
type i.e. the connections leave the component at one end, axial
types are also available. This is a type of polarised capacitor so
care is required to ensure correct polarity ( positive / negative
connection) in use.
Typical applications
include values above 1uF where this is just about the only type
available. |
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Ceramic Disc
Capacitor
As the name implies this
capacitor has a ceramic dielectric and is non-polarised
Applications include
requirements where high stability and low cost are
required. |
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A filament lamp ES
type.
A typical filament lamp
used in torches and simple indicator applications where power drain
is not a consideration. |
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A LED (Light Emitting
Diode)
A standard light emitting
diode the main use of these is as a low power long life indicator.
Various shapes colours and brightness levels are available. Polarity
is important and can be determined by either a small flat spot, at
the base of the mouldings, adjacent to the cathode or by the longer
connecting lead being the anode. |
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A typical 7 segment LED
display.
These consist of seven
LEDs arranged to produce a figure eight when all are lit. A further
LED may be employed as a decimal point indicator. Two variants are
available Common Cathode and Common Anode. In the later case all the
anode terminals from the LEDs are connected together internally and
brought to a connecting pin(s) on the back.
Due to the large
operating current of LED displays, LCD displays have become more
popular in battery powered equipment.
Common anode symbol
shown |
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Miniature Electric DC
Motor.
A small DC (Direct
Current ) motor suitable for light power model applications. This
design employs a permanent magnet and three pole wound armature
construction. Contacts to the armature are made via a small pair of
brushes and a commutator. With three poles the motor will start
easily from any position the direction of rotation being governed by
polarity of the supply. |
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