5325 results about "Electromotive force" patented technology

A motor driving method for driving a direct-current (DC) motor, designed for avoiding a reverse current induced by the Back Electromotive Force (BEMF), includes providing a driver circuit for driving the DC motor; comparing a signal level of a terminal of the DC motor and a predetermined voltage value to produce a comparing result; and controlling a specific lower gate switch to avoid the occurrence of a reverse current of the DC motor according to the comparing result.

The present invention provides an amplifying repeater, which is constructed in such a manner that a ferrite core is inserted into a coil with a pre-determined number of winds to increase an induced electromotive force caused by an increase in flux linkage using a time-varying magnetic field of electromagnetic waves at a position distant from various electromagnetic wave generating sources by a predetermined distance and the induction coil and a variable condenser for inducing resonance are connected to each other to increase current while reducing a resistant component existing in the induction coil to intensify and amplify the magnetic field of electromagnetic waves. Furthermore, the present invention provides a wireless power conversion charging device using the magnetic field of electromagnetic waves, which is located between an electromagnetic wave generating source transmitter and a receiving coil or attached to the transmitter and receiving coil. The wireless power conversion charging device includes a rectifying diode for rectifying an electromotive force induced in a construction in which a resonance and impedance matching variable condenser is connected to a coil in series or in parallel in order to transmit maximum induced power to a charging battery that is a load using electromagnetic waves amplified by the amplifying repeater, and a smoothing condenser for smoothing the rectified voltage. Accordingly, charging power required for various small power electronic devices can be provided and power can be supplied to various loads.

An immersion lithographic apparatus includes a voltage generator or power source that applies a potential difference to an object in contact with the immersion liquid such that bubbles and / or particles in the immersion liquid are either attracted or repelled from that object due to the electrokinetic potential of the surface of the bubble in the immersion liquid.

An electromagnetic pedicle awl utilizes a tightly focused time-varying magnetic flux to create a localized electromotive force (EMF) near the tip of a pedicle awl. The localized EMF creates localized eddy currents in nearby nerves which in turn excite ionic nerve channels, the excitation being detected by an electromyographic recording device. In comparison to the electrically stimulated pedicle awl of the prior art, the electromagnetic pedicle awl only excites nerves directly in front of and directly to the side of the tip. The electromagnetic pedicle awl is comprised of a tapered awl or drill tip in combination with a solid core surrounded by a solenoid. A pulsed electric current source drives the solenoid to create a time-varying magnetic field in the vicinity of the tapered tip. The awl or drill tip may be stationary with respect to the solenoid or it may rotate. The electromagnetic pedicle awl in combination with an EMG detector connected to a patient is very sensitive to the pedicle hole position with respect to adjacent nerves and reduces false placement failure.

Various embodiments of an electric motor and electronic control for an electric motor are disclosed. An exemplary electric motor comprises a single-phase brushless permanent magnet electric motor. In exemplary embodiments, the electronic motor control is configured to commutate an electric motor at a frequency other than line frequency, perform pulse width modulation, and drive the electric motor with a drive waveform that approximates the counter-electromotive force of the motor.