| Actuation Force |
– |
The force required to change the actuator of a switch from one position to the other. Unit of measure: lbs., oz., grams, torque. |
| Actuator |
– |
The movable part of a switch which causes a change in the electrical output. Example: slider, rotor, shaft, button. |
| Alternate Action |
– |
See Push-Pull. |
| Angle of Throw |
– |
The angle or arc through which an actuator passes during actuation. Typically used to refer to the movement of a toggle or rocker actuator. Unit of measure: degree. |
| Antistatic |
– |
A device that will withstand a specified potential without conducting between the actuator and any conducting element, usually the terminals or bushing. Unit of measure: typical value 15-20 kVDC. |
| Bounce |
– |
See Contact Bounce. |
| Break-Before-Make (BBM) |
– |
On actuation, the movable contact breaks contact with one fixed contact before making contact with another fixed contact. Contrast with Make-Before-Break (MBB). |
| Breakdown Voltage |
– |
See Dielectric Strength. |
| Break First |
– |
See Break-Before-Make. |
| Butt Contact |
– |
A contact mechanism in which the movable contact makes contact with the fixed (stationary) contact without a wiping motion between the surfaces. |
| Capacitive Load |
– |
A load in which the initial current on making (closing) of the contacts is higher than the steady state current. On breaking (opening) of the contacts, the current is less than the steady state. Current leads voltage in a capacitive load. |
| Carrying Current |
– |
The maximum current that can be passed through the closed contacts of a switch. Contrast with Current Rating. |
| Closed Circuit Current |
– |
The current passing through a set of closed contacts. |
| Contact (Contact Area) |
– |
The metal surfaces that come into physical contact to complete an electrical circuit. These surfaces are found on movable contacts. |
| Contact Bounce |
– |
The time during switching in which electrical instability, caused by the rebound of the contacts, is observed. Unit of measure: millisecond. |
| Contact Gap |
– |
The distance between a stationary contact and a movable contact in the open position. |
| Contact Rating |
– |
The capacity to switch (connect or interrupt) an electrical load. Unit of measure: volts, amps, load characteristic (resistive, inductive, capacitive or power factor). Contrast with Non-Switching Rating. |
| Contact Resistance |
– |
The total resistance of the switch, comprised of the contact interface and terminals. Unit of measure: milliohms. |
| Cycles |
– |
The number of times a switch can be actuated from one extreme position to the opposite extreme position and back to the original position. |
| Detent |
– |
A mechanical stop that holds the contacts in a given position after the actuation force is removed or prevents the changing of a contact position at less than a specified actuation force. |
| Detent Angle |
– |
The angle or arc between detent positions in rotary actuated switches. Unit of measure: degree. |
| Dielectric Strength |
– |
The ability of an insulator to withstand a voltage without arcing across its surface. Most often applies to insulator between terminals and metal exposed to operator of a switch. Unit of measure: volts RMS, VAC. |
| DIP or DIL |
– |
Dual-in-line package (in Europe DIL = Dual-in-line) refers to the switch package configuration. The package is rectangular with two rows of in-line terminals most commonly 0.100 " pitch, with 0.300 " spacing between rows. |
| Dry Circuit |
– |
See Dielectric Strength. |
| Dynamic Contact |
– |
A contact that can be moved by the switch actuator to make and break with one or more fixed contacts. |
| Electrical Life |
– |
The number of operations at a given electrical load that does not result in a degradation of any electrical or mechanical parameter beyond the standard set by the applicable end-of-life criteria. Unit of measure: cycles (on-off operations). |
| End of Life Criteria |
– |
Those specifications that a switch must meet at the end of its specified electrical life. Typically contact resistance and/or heat rise of contacts at full rated load at end of life. |
| Fixed Contact |
– |
The non-moving contact.Typically integral to the end of the terminal inside the switch body. |
| Gold Flash |
– |
A plating of gold typically less than 10 µin (millionths) thick. Used only as a barrier to oxidation or corrosion of terminals and to maintain solderability. |
| From Mounting Surface (FMS) |
– |
Used to describe the height, a physical dimension, of an electronic component from the surface of the printed circuit board to the top of the device. |
| Heat Rise |
– |
An indirect measurement of contact resistance used by rating agencies. The temperature rise over ambient of a contact set by carrying a prescribed current is measured to determine whether it falls within safe limits. |
