Electric Switches Types and Terms
Types of Electric Switches
-
have a plastic disk (cam) over which contoured surface a mechanical
follower moves, controlling the contacts. The cam is attached to and
rotated by a handle shaft.
- open or close the connections of two conductors
to a pair of separate circuits. DPDT switches, which usually have six
terminals, can be set to maintain contact, alternate contact or have
momentary contact.
- open or close the connection of a pair
of circuit conductors in a single circuit. DPST switches usually have
four terminals.
- are a set of small-sized ON-OFF switches. DIP
switches are used in place of jumpers and in such electronics as garage
door openers, personal computers and paintball marker electro-chips.
- change the flow of electric current.
-
are similar to safety switches, except they are manually operated. Enabling
switches are designed to protect workers in more hazardous environments
in which there is heavy machinery.
-
are activated by use of a fitting key. The key is turned to one of
several positions, triggering the switch.
-
are activated by turning a lever that is connected to a pivot point.
Lever switches typically have three positions.
-
are utilized in monitoring and for the control of machinery and industrial
equipment. Limit switches come in many different sizes and configurations.
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stay in the selected position when the handle is released.
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are used in applications that require compact mechanisms, such as handheld
equipment.
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are used for the positioning and control of industrial equipment and
machinery.
-
convert pressure changes to electrical functions.
-
are so called due to their activation method, which is usually in the
form of a plunger that, when pushed down, opens or closes the switch.
The configurations of these mechanical switches can be single-pole single-throw
(SPST), single-pole double-throw (SPDT), double-pole single throw (DPST),
double-pole double throw (DPDT) or solid state.
-
feature two contact blades, called ferromagnetic reeds, which are encapsulated
in glass. The reeds close when exposed to a magnet.
- are electric switches that are activated by rocking the switch to one side.
-
are triggered when there is tension in the safety cable. Rope pull
switches provide safety and monitoring contacts in the printing,
food processing and pharmaceutical industries.
-
have contacts that are arranged in a full or partial circle, which
means the mechanism that selects the contact must be turned. Rotary
switches, which may be manual or automatic, are used in such applications
as automobile distributions or ignition switches.
-
feature integrated actuators, which serve to protect both equipment
and personnel. This is done by monitoring the positions of movable components.
- , also referred to as "three-way
switches," open or close the connection of one conductor with
one of two other conductors. SPDT switches often have three terminals
and are sometimes used in pairs.
- , also called a "single-pole switches,"
open or close the connection of one conductor in a single circuit. SPST
switches usually have two terminals.
-
are designed to very quickly move their contacts from one location to
another. Mouse buttons and appliance settings use such switches.
-
have only two positions. Light switches and the caps lock key on a computer
keyboard are examples of toggle switch applications.
Electric Switch Terms
-
A mechanism that puts something into automatic action. In electrical
switch terms, actuators include plungers, plain levers, simulated
roller levers, etc.
- An
electrical current that intermittently changes direction of flow.
- A unit
of measurement that is used to define switch sensitivity. AT is calculated
by the number of turns of the coil in which the switch is tested and the
current (expressed in amps) that flows through the coil.
- The opening of a circuit,
the act of which prohibits current flow.
- A closed path along
which an electric current flows.
- A mechanism consisting
of a spring and starwheel that holds a switch in a specified position.
- An electric
current that flows in only one direction.
- The point at
which the switch contacts simply release, expressed in ampere-turns.
- The part of an electric
circuit connected to the earth that has a zero potential. Most electric
switches have ground connections.
- The ability of a
relay to have its contacts opened or closed upon command and remain in
that position until another command is given.
- The closing of a contact,
the act of which permits current flow.
-
The maximum load, referred to as amperage, that an electric switch is
capable of carrying.
- A term
that refers to a switch which is closed and connected in its normal position.
- A term
that refers to a switch which is open and disconnected in its normal position.
- A small rigid bar that is attached to a pivot
point and is activated by being pushed one way or another. Lever switches
normally have two or three positions.
- A type of actuator
that is activated with a push or thrust.
- An independent electrical
circuit of a switch.
- The specific point
at which an element of an electrical switch functions, expressed
in psi, psia or inches of mercury.
- The position in a
circuit at which a connection is normally established or broken.
- A
plastic
material that can be heated and expanded, as well as cooled and stiffened,
without any significant chemical change. Thermoplastics serve as dedicated
housing to some switches.
- A specified performance
limit given to switches. Volts (V) and amperes (amps) are the standard
units for establishing ratings.