Key switch
Key switches and key switches are electrical switches that are combined with a lock for security reasons . The switching process can therefore only be carried out by an authorized group of people with the aid of the appropriate key.
A key switch is used to trigger an impulse, for example to select the floor in an elevator, the key can only be removed in one position.
With a key switch, the key can lock in two or more positions, can usually be removed in any lock position and is used to set a switching state, for example for a sliding door ( open , closed , exit only , automatic ). Pressing a key switch is sometimes referred to as break referred.
The purpose of use is mostly to secure critical switching processes that are particularly worth protecting. Examples:
- Starting a motor vehicle ( ignition lock )
- Operation of potentially dangerous equipment (e.g. waste compactor)
- Switching on a circuit in the laboratory
- Resetting an emergency stop
- (Dis) arming an alarm system
- (Preferential) control of elevators
- Identification to an access control system or its control (e.g. gate operator)
- Operation of special traffic lights by vehicle drivers in public transport
Card readers, which can be found at many credit institutions, are related to the key switch. To do this, the card is inserted into the reader's slot and the door can then be opened. The iris or fingerprint scanners ( biometrics ) also serve a similar purpose .
literature
- Dieter Nührmann: The large work book electronics. Franzis, Poing 2001, ISBN 3-7723-5575-7 .
