Elastomeric connector
In electronics, conductive rubber is used instead of metallic conductors when only small currents to be transmitted. Consists of conductive rubber with carbon particles ( graphite, carbon black ) filled gum.
Conductive rubber is used either instead of resilient electrical multiple contacts or as a partner of a switching contact.
The electric conductivity of conductive rubber is considerably lower than that of metallic contacts or connections.
Multiple connections
An example of elastic permanent connections are the connecting webs (English rubber plugs or display rubbers ) between liquid crystal displays with the associated circuit board. They are in the art also called " zebras " because it consists of a plurality of parallel Leitgummistücke (black ), separated by non-conductive rubber (light) exist. The connector often contains much more Leitgummielemente than there are pads, so that the gaps between the pads are also not short-circuited, when the position of the zebra deviates during assembly. It is therefore not critical.
The use of such Leitgummiverbindung is necessary especially in liquid crystal displays, as their contact surfaces are very thin and can not be soldered or contacted metallic. However, it can be connected to this connection method, two circuit boards. The advantage of this Leitgummiverbindungen also lies in the elasticity, so you can ensure a safe connection of the many compounds of the display to the circuit board even when shaken eg small enclosures such as in mobile phones, quartz watches, digital panel meters or bicycle speedometers. The conductive rubber are exposed to a certain pressure and thus combine circuit board and LCD display electric shock and relatively safe.
However, problems may occur with high humidity. Through the capillary water gets between conductive rubber and screen or board and can cause short circuits. The Leitgummiverbindungen must therefore always be dry.
The long-term stability of Leitgummiverbindungen is also limited because deforms over time, the conductive rubber and plastic hardens. Thus, the secure contact is no longer assured, as soon as remove the pads back slightly, eg due to variations in temperature, mechanical deformation or change of position.
Grope
In conductive rubber keys can be used as a contact partner if frequent operation and low currents are present. The switch contacts consist of a comb-like interdigitated structure of two conducting surfaces (graphite or gold, for example, on a circuit board ). The Leitgummistück connects when you press the two surfaces together.
Conductive rubber buttons can be found in computer keyboards, mobile phones, remote controls and also in individual buttons for PCB mounting.
The conductive rubber piece is usually embedded in an elastic piece non-conductive rubber which closes tightly to the contact structure or the circuit board or the push button housing. Leitgummitasten are therefore often washable. They are very safe and reliable and have a low bounce on.