Have you heard of PCB membrane switches? Short for “printed circuit board,” this style of membrane switch is characterized by the use of a switch that’s been printed or etched. Acid-resistant solder is applied over the PCB, and the remaining exposed areas are then etched away by applying acid. The solder protects the key components of the membrane switch, whereas the remaining parts are etched away.
Depending on the application for which it is used, gold plating may be required on a PCB membrane switch. Air bag switches, for instance, are a critical component in modern day trucks and cars. If an airbag accidentally goes off while the car is driving, it could lead to serious injury or death. Therefore, automakers tend to use gold-plated PCB membrane switches to protect against accidental discharge.
So, what are PCB membrane switches made of? There are several different configurations available, though most are made of copper-covered cloth or fiber infused with a resin material. Arguably, the single most common and widely used material for use in PCB membrane switches is FR-4. Regardless of the materials used in its construction, PCB membrane switches offer an effective and versatile solution for a wide range of applications. Among other things, they are used in light-emitting diodes (LEDs), connectors, liquid-crystal displays (LCD), sensors, audio equipment, human machine interfaces (HMI) and more.
Of course, PCB membrane switches offer several benefits, some of which include lower resistance and higher conductivity, solid and durable design, high level of reliability, small and compact, gold plating options, and they can withstand some of the harshest environments (indoors and outdoors). They also use hard soldering techniques instead of epoxy, which usually promotes a longer lifespan.
It’s important to note that there are also the flex membrane switches. While similar to PCB membrane switches, flex switches are slightly different. They use thin dielectric materials instead of the fiber material found in PCB membrane switches. In doing so, it allows for die-cutting of components, which in turn reduces the cost of parts and tooling. However, flex membrane switches require the use of a support panel, similar to a silver circuit membrane switch.
Flex membrane switches share many of the same benefits as its PCB counterpart, including lower resistance and higher conductivity, solid and durable design, high level of reliability, small and compact, gold plating options, etc.