481results about How to "Minimise current" patented technology

A method and device for cooling and electrically-insulating a high-voltage, heat-generating component, for example, an x-ray tube (1105) for analyzing fluids by means of x-ray fluorescence. The device includes an x-ray source (1100) including an x-ray tube (1105) having improved heat-dissipating properties due to the thermal coupling of the x-ray tube with a thermally-conductive, dielectric material (1150). The device may include a base assembly (1135) mounted to the component for conducting heat away from the component while electrically isolating the component. In one aspect of the invention, the base assembly includes two copper plates (1140, 1145) separated by a dielectric plate (1150). The dielectric plate minimizes or prevents the leakage of current through the base assembly (1135). One aspect of the disclosed invention is most amenable to the analysis of sulfur in petroleum-based fuels.

An audio preamplifier (10) based on an operational transconductance amplifier, in combination with a class D audio output amplifier (12) is disclosed. The input signal is coupled to the preamplifier (10) through a capacitor (14) in series with a resistor (17) that sets the transconductance of the preamplifier. The preamplifier (10) includes a differential operational amplifier (20) that drives output MOS transistors (22a, 22b), which are biased by current sources (24a, 26a; 24b, 26b). Feedback from the drain nodes of the output MOS transistors (22a, 22b) to the inputs of the differential operational amplifier (20), along with the series capacitor (14) and resistor (17) input coupling, ensures minimum offset voltage and current at the output of the preamplifier (10). Common mode feedback control amplifiers (25, 29) ensure proper bias of the components into the saturation region.

A highly efficient fast charger for high capacity batteries and methods for fast charging high capacity batteries. The fast charger preferably comprises a rectified AC input of single or preferably three phases, with an optional power factor corrected input, minimally filtered with high frequency, high ripple current capacitors, which is switched with a power switching circuit in the “buck” configuration into an inductor / capacitor output filter. Metallized film capacitors are employed, to minimize the rectified 360 Hertz AC component filtering while providing transient switch protection and ripple current requirements for the buck regulator, to provide a high current fast charger with substantially improved power factor. High power, high frequency switching with minimized output filter size provides a highly filtered DC output. The fast charger is adapted to be constructed in a modular design for simple maintenance.

A MOS or CMOS based active pixel sensor designed for operation with zero or close to zero potential across the pixel photodiodes to minimize or eliminate dark current. In preferred embodiments the pixel photodiodes are produced with a continuous pin or nip photodiode layer laid down over pixel electrodes of the sensor. In this preferred embodiment, the voltage potential across the pixel photodiode structures is maintained constant and close to zero, preferably less than 1.0 volts. This preferred embodiment enables the photodiode to be operated at a constant bias condition during the charge detection cycle. Setting this constant bias condition close to zero (near “short circuit” condition) assures that dark current is substantially zero.

An improved induction tool for formation resistivity evaluations. The tool provides electromagnetic transmitters and sensors suitable for transmitting and receiving magnetic fields in radial directions that are orthogonal to the tool's longitudinal axis with minimal susceptibility to errors associated with parasitic eddy currents induced in the metal components surrounding the transmitter and receiver coils. The present invention provides increased effective tool surface impedance by increasing self-inductance of the paths in which induced eddy currents flow on the surface of the multi-component induction instruments. The tool enables downhole tool designers to build more effective and better-protected radial induction arrays for existing and future downhole instruments operating in the frequency and / or time domains. In this case the array measurement results contain information primarily about the formation's vertical resistivity. The tool makes it possible to combine radial arrays with coaxial arrays that conventionally measure horizontal formation resistivity. This combination enables obtaining a full resistivity tensor to evaluate formation resistivity anisotropy. The tool provides a composite non-conductive housing to reduce or even avoid the effects of parasitic eddy currents flowing on the tool surface. The tool provides a non-magnetic housing that is conductive which reduces the effects of conductive materials near coils and, primarily, the receiver. The tool provides a non-conductive coating is placed over the housing to prevent high frequency eddy currents from leaking from the housing in the conductive mud of the adjacent wellbore and returning to the housing.

The present invention provides robotic surgical instruments and systems that include electrosurgical cutting / shearing tools and methods of performing a robotic surgical procedure. The surgical instruments can advantageously be used in robotically controlled minimally invasive surgical operations. A surgical instrument generally comprises an elongate shaft having a proximal end and a distal end. An end effector, for performing a surgical operation such as cutting, shearing, grasping, engaging, or contacting tissue adjacent a surgical site, is coupleable to a distal end of the shaft. Preferably, the end effector comprises a pair of scissor-like blades for cooperatively shearing the tissue. A conductor electrically communicating with at least one blade delivers electrical energy to tissue engaged by the blades. An interface coupled to the proximal end of the shaft and removably connectable to the robotic surgical system is also included.

A charging apparatus for electrically charging a capacitor storage type power source comprises a switching circuit for turning on / off the charge current, a current detection circuit for detecting the charge current, a voltage detection circuit for detecting the voltage of power source, a constant current control circuit for outputting an error amplifying signal according to the current value, a power control circuit for outputting an error amplifying signal according to the current value, the voltage value-and a power reference value, a constant voltage control circuit for outputting an error amplifying signal according to the voltage value and a voltage reference value, an OR circuit for selecting one of the error amplifying signals and a control circuit for generating a pulse width modulation signal according to the error amplifying signal output from the OR circuit to turn on / off the switching circuit and control the charge current.