A distance measurement system includes a tank circuit including a transmit coil coupled to a transmit capacitor, a distance calculation circuit coupled to the transmit coil, and a target resonant circuit including a receive coil coupled to a receive capacitor. The receive coil is to receive a magnetic field generated by the tank circuit. The distance calculation circuit is to determine a reflected admittance. The reflected admittance includes a real component and an imaginary component. The distance calculation circuit is to determine a distance between the transmit and receive coils based on the imaginary component of the reflected admittance.

A method and a system may inductively determine a position of a display screen of a computing device. Associated processes may generate a magnetic field by providing an alternating current to a driver coil, and may generate a voltage at a sensor coil in response to the magnetic field. The system and method may additionally include determining a linear position of the display screen by executing an algorithm at a processor. An input to the algorithm may include voltage data associated with the voltage generated at the sensor coil. The linear position of the display screen may correspond to a size of the display screen between a minimum size and a maximum size.

A position detection device for detecting a position of a displaceable detection object includes a substrate, a transmitter coil and a receiver coil. The substrate is disposed facing the detection object. The transmitter coil extends in a plane direction of the substrate. The receiver coil in which wiring is formed in a spiral shape and aligned in a direction of displacement of the detection object includes a plurality of spiral portions which are inductively coupled by electromagnetic induction caused by current passing through the transmitter coil, a connecting wire which electrically connect the plurality of spiral portions to each other, and a parallel wire which is electrically connected to the spiral portions and the connecting wire and extends parallel to the connecting wire.

Provided is a position indicator of an electromagnetic induction type including a position indicator cartridge housed in a hollow portion of a housing, in which the position indicator cartridge includes a first resonant circuit including a first coil wound around a magnetic core arranged on one end of the position indicator cartridge in an axial direction of the position indicator cartridge and a first capacitor, a second coil that is independent of the position indicator cartridge provided outside of the position indicator cartridge, at a position where the second coil, in operation, is magnetically coupled to the first coil of the position indicator cartridge, and a switch turned on and off by an operation portion provided outside of the position indicator cartridge, the operation portion, in operation, receiving an operation of a user, and a closed circuit including the second coil is formed when the switch is turned on.

Example positioning system based on a low frequency magnetic field and apparatus are described. One example positioning system includes a low frequency magnetic field transmit apparatus and a low frequency magnetic field receive apparatus. The transmit apparatus includes a transmit coil, a conflict detect coil, and a magnetic field generation detection control module. The receive apparatus includes a receive coil and a magnetic field detection control module. When the conflict detect coil does not sense a low frequency magnetic field signal, the magnetic field generation detection control module controls the transmit coil to transmit a first low frequency magnetic field signal. When the received low frequency magnetic field signal is the first low frequency magnetic field signal, the magnetic field detection control module determines relative positions of the transmit coil and the receive coil based on signal strength of the first low frequency magnetic field signal.

A position indicator of an electromagnetic induction type. The position indicator includes a first resonant circuit, a second coil, and a switch. The first resonant circuit includes a first capacitor and a first coil wound around a magnetic core arranged on one end of the position indicator in an axial direction of the position indicator. The second coil is independent of first coil, at a position where the second coil, in operation, is magnetically coupled to the first coil. The switch is connected electrically to the second coil. A closed circuit including the second coil is formed when the switch is turned on.