Abstract: A light emitting diode lamp includes a light source configured to emit light that defines a spectral power distribution curve including a first power peak and a second power peak with a first reduced power area extending therebetween. The first reduced power area defines a first reduced power area minimum in a green color region of the spectral power distribution curve and the spectral power distribution curve compares a power of the light versus a wavelength of the light.

Abstract: A circuit for mitigating electric shock including an external impedance detection circuit and a test and holdoff circuit. The external impedance detection circuit detects a presence of an external impedance, such as by detecting a relative change in voltage from a startup condition and a test condition. The test and holdoff circuit inhibits operation of a power converter which delivers power to be consumed by a load. The startup condition is defined by mains power applied to the circuit with negligible power consumed by a load. The test condition is defined by non-zero power delivered to the load. According to another aspect, the external impedance detection circuit measures an input voltage using a high input power which is greater than a shock hazard threshold at a duration less than a threshold time duration and determines the presence of the external impedance based on low pass filters having different time constants.

Abstract: A lamp includes a first pair of primary electrical contacts configured to be electrically connected to a AC mains, a second pair of primary electrical contacts configured to be electrically connected to a non-switched emergency mains, and a battery charge controller in electrical communication with the second pair of electrical contacts. The lamp also includes a battery pack in electrical communication with the battery charge controller, an AC mains driver electrically connected to the first pair of primary electrical contacts, an emergency driver electrically connected to the battery pack, and an LED array in electrical communication with the AC mains driver and the emergency driver.

Abstract: A lamp includes a first pair of primary electrical contacts configured to be electrically connected to a AC mains, a second pair of primary electrical contacts configured to be electrically connected to a non-switched emergency mains, and a battery charge controller in electrical communication with the second pair of electrical contacts. The lamp also includes a battery pack in electrical communication with the battery charge controller, an AC mains driver electrically connected to the first pair of primary electrical contacts, an emergency driver electrically connected to the battery pack, and an LED array in electrical communication with the AC mains driver and the emergency driver.

Abstract: A tubular light emitting diode lamp includes a lamp body, a plurality of light emitting diodes disposed on the lamp body, and a first lamp base and a second lamp base that are disposed at opposite ends of the lamp body. At least one of the first lamp base and the second lamp base includes at least one primary pin and at least one secondary pin. The tubular light emitting diode lamp also includes a driver electrically connected to the plurality of light emitting diodes, the at least one primary pin, and the at least one secondary pin. The least one primary pin provides power to the driver to cause the plurality of light emitting diodes to emit light and the at least one secondary pin provides a signal to the driver that is distinct from the power.

Abstract: A circuit for mitigating electric shock including an external impedance detection circuit and a test and holdoff circuit. The external impedance detection circuit detects a presence of an external impedance, such as by detecting a relative change in voltage from a startup condition and a test condition. The test and holdoff circuit inhibits operation of a power converter which delivers power to be consumed by a load. The startup condition is defined by mains power applied to the circuit with negligible power consumed by a load. The test condition is defined by non-zero power delivered to the load. According to another aspect, the external impedance detection circuit measures an input voltage using a high input power which is greater than a shock hazard threshold at a duration less than a threshold time duration and determines the presence of the external impedance based on low pass filters having different time constants.

Abstract: A light emitting diode lamp includes a light source configured to emit light that defines a spectral power distribution curve including a first power peak and a second power peak with a first reduced power area extending therebetween. The first reduced power area defines a first reduced power area minimum in a green color region of the spectral power distribution curve and the spectral power distribution curve compares a power of the light versus a wavelength of the light.

Abstract: A lamp includes a first pair of primary electrical contacts configured to be electrically connected to a AC mains, a second pair of primary electrical contacts configured to be electrically connected to a non-switched emergency mains, and a battery charge controller in electrical communication with the second pair of electrical contacts. The lamp also includes a battery pack in electrical communication with the battery charge controller, an AC mains driver electrically connected to the first pair of primary electrical contacts, an emergency driver electrically connected to the battery pack, and an LED array in electrical communication with the AC mains driver and the emergency driver.

Abstract: A tubular light emitting diode lamp includes a lamp body, a plurality of light emitting diodes disposed on the lamp body, and a first lamp base and a second lamp base that are disposed at opposite ends of the lamp body. At least one of the first lamp base and the second lamp base includes at least one primary pin and at least one secondary pin. The tubular light emitting diode lamp also includes a driver electrically connected to the plurality of light emitting diodes, the at least one primary pin, and the at least one secondary pin. The least one primary pin provides power to the driver to cause the plurality of light emitting diodes to emit light and the at least one secondary pin provides a signal to the driver that is distinct from the power.

Abstract: An LED lamp has dual modes of operation from fluorescent lamp fixtures. A first circuit powers at least one LED in a first mode of operation when first and second power pins at a first end of the lamp are inserted into power contacts of the fixture that are directly connected to power mains. A second circuit powers at least one LED in a second mode of operation when the second power pin at the first end of the lamp and a third power pin at a second end of the lamp are inserted into power contacts of a fixture powered from an electronic ballast. First and second conduction control means permit the second circuit to power at least one LED during the second mode of operation.

Abstract: An LED lamp has dual modes of operation from fluorescent lamp fixtures. A first circuit powers at least one LED in a first mode of operation when first and second power pins at a first end of the lamp are inserted into power contacts of the fixture that are directly connected to power mains. A second circuit powers at least one LED in a second mode of operation when the second power pin at the first end of the lamp and a third power pin at a second end of the lamp are inserted into power contacts of a fixture powered from an electronic ballast. First and second conduction control means permit the second circuit to power at least one LED during the second mode of operation.

Abstract: An LED lamp has dual modes of operation from fluorescent lamp fixtures. A first circuit powers at least one LED in a first mode of operation when first and second power connector pins at a first end of the lamp are inserted into power receptacles of the fixture that are directly connected to power mains. A second circuit powers at least one LED in a second mode of operation when the second power connector pin at the first end of the lamp and a third power connector pin at a second end of the lamp are inserted into power receptacles of a fixture powered from an electronic ballast. First and second conduction control means permit the second circuit to power at least one LED during the second mode of operation.

Abstract: Systems, methods, and other embodiments associated with controlling the specific absorption rate (SAR) in a patient associated with a conductor are described. The conductor may be, for example, a wire associated with a pacemaker, a wire associated with a neurostimulator, an orthopaedic device, and so on. One example method includes calibrating a multi-channel transmitter associated with a magnetic resonance imaging (MRI) apparatus imaging the patient. The example method also includes controlling the MRI apparatus to transmit radio frequency (RF) energy to image the patient in a manner where the RF energy will only influence the SAR near the conductor in the patient less than a desired threshold amount.

Abstract: Example systems, apparatus, circuits, and so on described herein concern a Hall effect current sensor that includes a planar portion of a conductor that is oriented perpendicular to a base magnetic field in which it is located. In the presence of the magnetic field, a differential voltage is produced across the planar portion that is proportional to a strength of the magnetic field and the amount of current flowing through the conductor.

Abstract: Example systems, apparatus, circuits, and so on described herein concern parallel transmission in MRI with on-coil current-mode (CMCD) amplifiers. One example apparatus includes switched voltage-mode class D (VMCD) pre-amplifiers. Another example apparatus includes amplitude modulation of the output of the CMCD amplifiers using feedback control based, at least in part, on a comparison of an envelope of transmit coil current to an envelope of an input RF pulse.

Abstract: Example systems, apparatus, circuits, and so on described herein concern parallel transmission in high field MRI. One example apparatus includes a balun network that produces out-of-phase signals that are amplified to drive current-mode class-D (CMCD) field effect transistors (FETs) that are connected by a coil that includes an LC (inductance-capacitance) leg. The LC leg is to selectively alter the output analog RF signal and the analog RF signal is used in high field parallel magnetic resonance imaging (MRI) transmission.

Abstract: Systems, methods, and other embodiments associated with mitigating off-resonance angle in steady-state coherent magnetic resonance imaging (MRI) are described. One example method includes accessing a B0 map and a coil sensitivity profile associated with an MRI apparatus configured to produce a steady-state coherent MRI sequence to image an object. The MRI apparatus is configured with a multi-channel transmission array having individually controllable transmission channels. The method includes computing transmission control parameters for individual transmission channels as a function of the B0 map and the coil sensitivity profile. The transmission control parameters are configured to facilitate controlling the transmission array to create a spatially varying phase profile using a single dimensional radio frequency (RF) pulse.

Abstract: Systems, methods, and other embodiments associated with MRI excitation are described. One example method includes performing a calibration to determine a set of transmission parameters for a set of excitation pulses for transmission channels available on a multi-channel MRI transmitter. The set of excitation pulses are configured to produce a resulting nuclear magnetic resonance (NMR) signal from an object exposed to the set of excitation pulses. The resulting NMR signal comprises NMR signal associated with a first NMR resonance associated with the object and NMR signal associated with a second NMR resonance associated with the object.

Abstract: Devices, systems, methods, and other embodiments associated with magnetic resonance imaging (MRI) are described. In one embodiment, an apparatus includes an RF coil for use in multi-nuclear excitation in magnetic resonance imaging (MRI). The RF coil includes a set of two or more L-C coils. Members of the set of two or more L-C coils have individual resonance frequencies. An RF amplifier is placed near the RF coil. The RF amplifier is controllable to selectively produce the individual resonance frequency of a member of the set of two or more L-C coils based, at least in part, on a digital input provided to the RF amplifier.

Abstract: Systems, methods, and other embodiments associated with controlling the specific absorption rate (SAR) in a patient associated with a conductor are described. The conductor may be, for example, a wire associated with a pacemaker, a wire associated with a neurostimulator, an orthopaedic device, and so on. One example method includes calibrating a multi-channel transmitter associated with a magnetic resonance imaging (MRI) apparatus imaging the patient. The example method also includes controlling the MRI apparatus to transmit radio frequency (RF) energy to image the patient in a manner where the RF energy will only influence the SAR near the conductor in the patient less than a desired threshold amount.