{
  "$type": "site.standard.document",
  "description": "The switching device comprises a capacitive sensor (1) connected to an electronic processing circuit comprising the following stages: (A) an oscillator-converter of the variations of capacitance into the variations of frequency, (B) a frequency-voltage converter, (C) a high-pass filter or…",
  "path": "/patents/1108081",
  "publishedAt": "2001-12-05T00:00:00.000Z",
  "site": "at://did:plc:oql6ds5vnff4ugar6rruliwd/site.standard.publication/3mn3ohu7oxx5w",
  "tags": [
    "B60R25/246",
    "DELPHI TECH INC [US]"
  ],
  "textContent": "The switching device comprises a capacitive sensor (1) connected to an electronic processing circuit comprising the following stages: (A) an oscillator-converter of the variations of capacitance into the variations of frequency, (B) a frequency-voltage converter, (C) a high-pass filter or differentiator, (D) a voltage amplifier, and (E) a monostable producing the output signal in the form of pulses. The capacitive sensor (1) consists of a metallic plate positioned on a capacitive structure equipped with elements controlled by switching. The metallic plate is insulated from the capacitive structure by an insulating layer of finite thickness to allow maintaining the capacitance of plate with respect to the structure at a minimum value. The oscillator-converter is based on a logic inverter with hysteresis, whose input and output are connected by a resistor for the frequency tuning. The input of inverter is connected to the sensor by a resistor, and by two protection diodes to the supply voltage and to the ground. The frequency-voltage converter is constituted by a capacitor coupled by a rectifier with two diodes to a filter capacitor connected in parallel with a resistor. The high-pass filter is constituted by a capacitor connected in series with a resistor. The voltage amplifier comprises an inverter with a feedback loop containing a resistor and a capacitor connected in parallel. The monostable is constituted by a transistor with the base connected to a capacitor in a serial input and the collector to a logic inverter in output. The metallic plate of sensor is fastened on the vehicle in the vicinity of a mechanism for door opening. The electronic processing circuit is connected to a transmitter-receiver which on contact detection transmits a radio-frequency signal to a manual transponder comprising a transmitter-receiver; the transponder on reception sends back an identification signal which authorizes the control of electronic system for locking/unlocking of doors.",
  "title": "Switching device operating by contact of human body"
}