Circuit - Overview
Overview | Design considerations
- Types
- Characteristic
PRINCIPAL FUNCTION: The flexible circuits, entirely designed and produced by GGI International, are the foundation of the membrane switch keypad operation. The function of the membrane switch keypad circuit is to translate the operator command into an electric signal which will be interpreted by the electronic interface on which the keypad is connected.
POSITION:
Its position inside a membrane switch/User Interface Assembly is variable and will depend on the type of circuit.
COMPOSITION:
GGI International generally prints its circuits on a nonconducting and thermostabilized .005" polyester film. GGI's screen-printing process is performed in a highly controlled environment (clean room). Conductive silver, carbon and dielectric inks will typically be part of a polyester membrane keypad circuit.
TYPE OF CIRCUITS: The design of a GGI International membrane switch keypads will be dictated by the type of circuit which the keypad will require. The main types of circuits most frequently used include:
- Circuit with domes
- Circuit with LEDs
- Circuit with a combination of domes and LEDs
- Independent circuit with domes and LEDs
- Circuit with domes on 2 circuits
- Non-tactile circuit
BASIC ELECTRICAL CHARACTERISTICS:
- Voltage and operating current: 1-30 VDC / 1 mA-100 mA / 1 Watt maximum
- Trace resistance: maximum of 100 ohms
- Contact resistance: 0.1 to 10 ohms
- Capacitance: maximum of 20 pF
- Insulation resistance: 100 megohms at 500 VDC
- Dielectric strength: 250 VRMS