QTC® SP Sensors are pressure sensitive membrane switches. There are two different sizes of sensor available, with 5mm and 10mm active areas.
The SP200 series utilise finger electrodes with electrical connection to just the one layer. A ‘patch’ of PET printed with carbon and overprinted with QTC® is then assembled over the finger electrodes with 50µm PSA adhesive around the outside of the active area only. This leaves a gap of approximately 20–30µm between the top electrode and the QTC® layer. In application, the finger electrodes could be printed onto a PCB or FPC if required.
With the SP200 series finger electrode design, two electrodes must be in contact for current to pass. 10mm SP200 series are more sensitive than the 5mm versions due to the narrower gap in the adhesive.
The range of usable force for SP200 sensors gives excellent active resistance change up to 2kg. In addition, SP200 sensors also show excellent stability to environmental conditions and high temperature operation.