| The following glossary contains definitions of
characteristics, options, and esoteric terms applicable to rotary
switches. It is in alphabetical order for ease of reference,
and can be useful to the designer in establishing specifications
to meet unique applications .
Glossary A-C - Glossary
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| |
| Term |
Definition |
| Add-A-Pot |
Add-A-Pot rotary switches include
a Potentiometer as part of the assembly. Concentric
shafts allow independent actuation of the switch and the
potentiometer.
Add-A-Pot is a popular custom modification available on many
of our switch lines. |
| Adjustable Stops |
Adjustable stops
are holes beneath the panel seal. Stop Pins are special
pins inserted in these holes, and act as position stops.
Stop pins allow the user to pre-select switch positions where
the range of motion stops. |
| Angle of Throw |
Number
of
Positions |
Degrees
between
Positions |
| 4 |
90¡ |
| 6 |
60¡ |
| 8 |
45¡ |
| 10 |
36¡ |
| 12 |
30¡ |
|
Number
of
Positions |
Degrees
between
Positions |
| 16 |
22¸¡ |
| 25 |
14.4¡ |
| 48 |
7¸¡ |
| 50 |
7.2¡ |
| 100 |
3.6¡ |
|
The angular degrees between positions. |
| Coded
Switches |
Rotary switches that convert positions
into a binary number:
- BCD (Binary Coded Decimal)
- Binary Base 2
- Octal (Base 8)
- Hexadecimal (Base 16)
- Gray Code
Custom Codings are also available. Please
Contact Us
The most popular binary codings available are:
   
|
| Common |
The common is one of the switches'
terminals, and is the terminal that is always part of the
switch circuit regardless of position. The common connects
to the different circuits via the individual stator terminals
as the shaft rotates from position to position.
Also called the pole. |
| Concentric Shafts |
Concentric shafts are two shafts on a common axis that
are independently actuated, performing separate switching
functions on the same assembly. |
| Concentric Shaft Switches |
A concentric shaft switch is one that has a shaft within
a shaft. For example, an outside hollow shaft of .250"
diameter with a .125" shaft inside it.
Each shaft works independently, actuating one or more decks,
each deck having different throw angles and number of positions.
In effect, it is like having two separate switches in one
panel location. |
| Conformal Coat |
A sealant used on switch
seams or terminal bases to safeguard against caustic, acidic,
or corrosive contamination by foreign substances.
Looking for protection against Flux Contamination,
Liquid Immersion? Cole can provide a rugged switch for your demanding
application! |
| Contact Chatter |
Contact discontinuity (open circuit)
experienced when a switch is subjected to physical vibration
or rotated to a new position.
Also called contact bounce. |
| Contact Resistance |
The Ohmic resistance of the switch
contact points, usually measured in milliohms.
This is particularly significant in "Dry
Circuit" or low level applications, since the resistance
varies significantly at the micro-amp level with current variations. |
Glossary A-C - Glossary
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| Term |
Definition |
| Decks |
Multi-Deck switches have sections,
each performing separate functions, that are axially stacked
around a common actuating shaft. |
| Detent |
A mechanism that
holds the switch in a given position after the actuating torque
is removed. It also prevents the switch from changing
positions unless a minimum specified actuating torque is applied
to the shaft.
You can depend on Cole to design and economically manufacture
a rugged switch with a precision detent of your exact specification. |
| Detent
Torque |
The peak actuating force required
to turn the rotary switch through its detented positions,
measured in inch-ounces or inch-pounds.
Also called Operating Torque. |
| D-Flat
Double-D |
 Terms describing the switch mounting bushing (ferrule)
or shaft physical configuration. "D-Flat" describes one flat
surface, while "Double-D" describes two parallel flat surfaces
on the periphery of a shaft or bushing. |
| Dielectric Withstanding Voltage |
This is the maximum
voltage that can be applied between open switch terminals
and the switch housing or mounting bushing (ground) without
arcing or flashover. Arcing or flashover indicates a
breakdown of the insulating material. A typical maximum
voltage is 250 to 1500 Vrms, depending upon the size of the
switch.
See also Insulation
Resistance. |
| Dry Circuit |
A term indicating
switch contacts designed for operation at currents less than
10 milliamps and at voltages less than 30 millivolts DC.
Also known as Low Level. |
| EMI/RFI Shield |
A special grounding technique that
guards the switch from being affected by ambient Electro-Magnetic
Interference (EMI), or Radio Frequency Interference (RFI).
EMI or RFI may negatively affect circuit functions.
These undesirable energy transients usually come through the
wiring (conducted), or the shaft (radiated).
Tests specified by MIL-S-3786 measure how these transients
are shunted to ground. |
| Epoxy
Seal |
A sealant used on
a switch assembly to safeguard against solder flux, cleaning
solvents, or other contaminants from entering the inside working
portion of the switch.
Looking for protection against Flux Contamination,
Liquid Immersion? Cole can provide a rugged switch for your demanding
application! |
| Explosion Proof |
A design feature that allows switch
actuation of electrical energy, without causing ignition,
while immersed in an enclosed area having a combustible
atmosphere. |
| Flux-Proof |
A switches' ability to withstand
contamination by flux used in the soldering process.
The flux is prevented from entering the internal mechanism.
Also see Conformal Coat, Epoxy
Seal. |
| GRAY Code |
A binary code that features the
change of only one bit to progress in either ascending or
descending sequence.
For other examples of binary codings, please see Coded
Switches. |
| Guarded Position |
A switch position
that requires a special action, such as pushing or pulling
the shaft, in order to enter or leave the position.
Also called a Locked-In or Isolated Position. |
Glossary A-C - Glossary
D-G - Glossary H-O - Glossary
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| Term |
Definition |
Insulation
Resistance |
This is the resistance measured
between open switch terminals, and between a switch terminal
and ground. The unit of measurement is usually Megohms.
See also Dielectric
Withstanding Voltage. |
Isolated
Position |
See Guarded
Position. |
| Key-Lock |
A security feature that
prevents switch actuation without insertion of a key. |
| Key-Pull |
A feature that
allows insertion of removal of the key in specified positions
only. |
Locked-In
Position |
See Guarded
Position. |
| Low Level |
See Dry
Circuit. |
| MIL-I-45208 |
A military specification that states
the requirements for an inspection system. |
| MIL-Q-9858 |
A military specification
that states the requirements for a quality system, including
downstream supplier control. |
| MIL-S-3786 |
A general military specification
for rotary switches. |
| MIL-S-3786/XX |
These are the specific
requirements for individual types of switches that must be
met before inclusion in the Qualified Products List (see QPL). |
| MIL-STD-202F |
A military standard defining test
methods for electronic and electrical component parts. |
| Momentary |
A switch position that incorporates
a spring return mechanism that restores the shaft to
a return position upon release. |
Non-Shorting
Contacts |
A "break-before-make" property
of switch operation that opens the preceding circuit before
closing the next.
See also Shorting Contacts. |
Operating
Torque |
See Detent
Torque. |
Glossary A-C - Glossary
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| Term |
Definition |
| Panel Seal |
A seal placed between the panel
and switch mounting surfaces to exclude leakage past the mounting
bushing.
Also see Shaft Seal. |
PC
Terminals |
Terminals on a
rotary switch specifically designed for mounting on a printed
circuit board.
See also Terminal. |
| Pole |
See Common. |
Precision
Rotary
Switch |
A precision rotary
switch is differentiated from a plain rotary switch in that
it is designed and manufactured to precise tolerances as well
as meeting stringent mechanical, electrical, and environmental
conditions. |
| QPL |
An acronym for "Qualified Product
List", it lists the slash numbers in the MIL-S-3786
specifications (e.g. MIL-S-3786 /04 ; /13 ; /20 ; /35 etc.)
that successfully meet the criteria of the qualification tests
designated therein.
Having products registered in the QPL allows manufacturers
to sell the specific part numbers with only a simple functional
acceptance test required for approval. |
| Ramp-In |
Ramp-In allows
a specific position to be attained through normal shaft rotation.
But, after that position is reached, a push or pull action
on the shaft is required to exit. |
| Ramp-Out |
Ramp-Out requires a push or pull
action on the shaft to enter a specific position. It
can be exited with a normal shaft rotation, however. |
| Rotor |
A device inside
the rotary switch, permanently affixed to the shaft, that
houses the moveable contact that closes circuits through
the stator terminals as it moves from position to position
by normal shaft rotation. |
| Shaft Flat |
The flat section of a round shaft
provided for the purpose of preventing the knob from slipping
during switch actuation. |
| Shaft Seal |
Almost always used in conjunction
with a Panel Seal, it performs
the same basic function of preventing leakage past the shaft. |
| Shock |
The impact a switch must withstand
without failure. |
| Shorting
Contacts |
A "make-before-break" feature
of switch actuation when going from one position to the next.
This is useful in preventing arcing during position change
since the next position is connected before the previous position
is disconnected.
See also Non-Shorting
Contacts. |
| Slotted Shaft |
A shaft that has a transverse slot
at the end, commonly used for actuation by a screwdriver. |
| Stator |
The fixed portion of a rotary switch
containing the terminals completing the circuit with the moveable
contact. |
| Stop Strength |
The maximum amount of torque that
a switch can withstand at the end of its travel without breaking.
This is usually measured in inch-pounds. |
Glossary A-C - Glossary
D-G - Glossary H-O - Glossary
P-S - Glossary T-Z - Glossary
of Terms Packet Download
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| Term |
Definition |
| Tease Proof |
Def. 1) A switch feature that
prevents intentional or unintentional partial rotation of
the contacts between positions, after removal of operating
torque
Def. 2) Prevents the switch mechanism from remaining
between positions, after removal of operating torque. |
| Terminal |
The means by which
a rotary switch connects to external circuitry. A few
common styles include:
- screw terminal
- printed circuit board terminal (PC
Terminal)
- solder lug
|
| Terminal Strength |
A measure of a switch terminal's
ability to withstand a pull test, usually measured in pounds. |
| Thermal Shock |
A test that subjects the switch
to rapidly changing temperature extremes. |
| Torque |
A rotational force around an axis. |
| Glossary
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