A classic switch has one input and one output. It can be NO (normally open) or NC (normally closed). A NC/NO switch has one input and two outputs and consequently 2 possible actions.


With a NC/NO switch, there are two output types: one switching and another non-switching. This double function is interesting in many applications, but let’s take a concrete example: a Push-to-talk headset. One single switch allows control of headphones and microphone. When the switch is not activated, the headphones are active, you can hear your interlocutor. By activating the switch, you turn the headphones off and activate the microphone, allowing you to communicate info on your turn. With the NC/NO function, the switch becomes multifunction. A single switch allows for 3 electric configurations: NC, NO and NC/NO. This allows optimization of equipment design and purchasing.


A NC/NO switch also provides a redundancy function. It allows to verify the good operation of the system and consequently of the equipment on which it is mounted. This is a real advantage in applications where safety is crucial (medical or military equipment). Miniaturizing this function is hard, that is why it is rare on the tact switch market. Our engineers have developed a specific dome shape allowing to keep the circuit closed when non-switching. The Multimec 5 series tactile switch is available with a NC/NO function and a life of 1 million cycles.