a capacitive lock can include various circuits that allow it to operate more efficiently and with greater accuracy . for example , when a user continuously touches a door handle for a certain time duration , a sensor can be configured to retain a variation in capacitance . when the door handle is continuously touched , a time constant circuit can be provided inside the entry system and measures the contact time and unlocks a door on the assumption that the user has a will to unlock and / or operate the vehicle or other apparatus .