Tact push-button has change-over contacts for monitoring

Oct 16, 2024

Littelfuse has introduced a ‘tact’ style push-button with change-over contacts.

‘KSC DCT’ as it will be known, has a 6.2 x 6.2mm surface-mount body and is sealed to IP67. Both gull-wing and J-lead leg variants are available.

“Everyone can now precisely monitor the actual status of an electromechanical surface-mount technology tactile switch, even when the switch is not in use, which helps discriminate a silent signal versus a device malfunction,” said Littelfuse v-p Jeremy Hebras.

Action is with a 4.75N (±1.25N) force and momentary – it springs back when touch is removed – with a travel of 0.85mm (+0.35mm, -0.25mm). Total height from PCB to actuator tip is 5.2mm.

The contacts are asymmetric.

The normally closed contact is rated for 40mV to 12V and 2 to 25mA, limited to 500mVA. Bounce is 20ms, contact resitance is 500mΩ, and 250Vac 50Hz can be withstood for 1 minute.

The normally-open contact is rated for 20mV to 24V and 1mA to 50mA, limited to 1VA. Its other figures are 3ms, 100mΩ and 125Vac.

Operation is over -40 to 85°C and estimated life is 300,000 cycles.

Automotive (door handle), consumer (power tool), medical and industrial applications are foreseen.

“In an automotive door handle, for example,” said the company, “both NC and NO circuitries are used before making any decision. The logic is at rest: the NC contact is closed while the NO contact is open. When a user pushes the button, nothing will happen until the NC contact is open and the NO contact is closed.”

Littelfuse tact switch activity springs from it acquiring C&K Switches in 2022.

KSC DCT switch web page