* Magnetic resonance imaging ( MRI ) MRI is a method of imaging objects that uses a strong magnetic field to detect the relaxation of protons that have been perturbed by a radio-frequency pulse.

These electrons interact with the radio-frequency magnetic field of the induction coil and are accelerated first in one direction, then the other, as the field changes at high frequency ( usually 27. 12 million cycles per second ).

These electrons interact with the radio-frequency magnetic field of the induction coil and are accelerated first in one direction, then the other, as the field changes at high frequency ( usually 27. 12 MHz ).

Rather than aligning the protons using a solenoid, a low power radio-frequency field is used to align ( polarise ) the electron spin of the free radicals, which then couples to the protons via the Overhauser effect.

This chip contains a radio-frequency electromagnetic field coil that modulates an external magnetic field to transfer a coded identification number when queried by a reader device.

MRI uses three electromagnetic fields: a very strong ( on the order of units of teslas ) static magnetic field to polarize the hydrogen nuclei, called the static field ; a weaker time-varying ( on the order of 1 kHz ) field ( s ) for spatial encoding, called the gradient field ( s ); and a weak radio-frequency ( RF ) field for manipulation of the hydrogen nuclei to produce measurable signals, collected through an RF antenna.

If the magnetic field in the plasma is not stationary, either because the plasma as a whole is transient or because the fields are periodic ( radio-frequency heating ), the rate of change of the magnetic field with time (, read " B-dot ") can be measured locally with a loop or coil of wire.

The Auto-ID Labs network is a research group in the field of networked radio-frequency identification ( RFID ) and emerging sensing technologies.

By applying both a magnetic field and carefully tuning a radio-frequency transmitter, the nuclear spins will flip and re-emit radiation, in an effect known as the Rabi cycle.

The advantage of plasma acceleration is that its acceleration field can be much stronger than that of conventional radio-frequency ( RF ) accelerators.

The end of this torch is placed inside an induction coil supplied with a radio-frequency electric current.

The end of this torch is placed inside an induction coil supplied with a radio-frequency electric current.

A radio-frequency alternating current is passed through a coil of wire that acts as the transmitter, and a second coil or conducting object, magnetically coupled to the first coil, acts as the receiver.

The heating is achieved by a radio-frequency current passed through a coil surrounding the plasma.

The welding apparatus contains an induction coil that is energised with a radio-frequency electric current.

It may contain digital, analog, mixed-signal, and often radio-frequency functions — all on a single chip substrate.

* Where the oscillator drives equipment that may generate radio-frequency interference, adding a varying voltage to its control input can disperse the interference spectrum to make it less objectionable.

Glow discharges may also be operated in radio-frequency.

Another technology, thermotherapy, uses radio-frequency energy to directly heat the bladder wall, which together with chemotherapy shows a synergistic effect, enhancing each other's capacity to kill tumor cells.

For high-power radio-frequency transmission up to about 1 GHz, coaxial cable with a solid copper outer conductor is available in sizes of 0. 25 inch upward.

In radio-frequency applications up to a few gigahertz, the wave propagates primarily in the transverse electric magnetic ( TEM ) mode, which means that the electric and magnetic fields are both perpendicular to the direction of propagation.

In military equipment the 807 / ATS25, with a rated anode dissipations of 25 watts and operating from a supply of up to 750 volts, was in widespread use as the final amplifier in radio-frequency transmitters of up to 50 watts output power and in push-pull applications for audio.

In radio communication, a continuous wave radio-frequency signal ( a sinusoidal carrier wave ) has its amplitude modulated by an audio waveform before transmission.

Despite some allegations that EMR exposure has negative health consequences, at this time, no link has been verifiably proven between the radio-frequency EMR that tin foil hats are meant to protect against and subsequent ill health.

Research activity in the area of radio-frequency ( RF ) circuit design has surged in the last decade in direct response to the enormous market demand for inexpensive, high-data-rate wireless transceivers.

The term " R / C " has been used to mean both " remote controlled " and " radio controlled ", where " remote controlled " includes vehicles that are connected to their controller by a wire, but common use of " R / C " today usually refers to vehicles controlled by a radio-frequency link.

The skin effect has practical consequences in the analysis and design of radio-frequency and microwave circuits, transmission lines ( or waveguides ), and antennas.

It has relatively high Miller capacitance, making it unsuitable for radio-frequency use.

The requirement to space these satellites apart to avoid harmful radio-frequency interference during operations means that there are a limited number of orbital " slots " available, thus only a limited number of satellites can be operated in geostationary orbit.

An isolating transformer or blocking capacitor can be used to couple a coaxial cable to equipment, where it is desirable to pass radio-frequency signals but to block direct current or low-frequency power.

In radio-frequency and fast switching circuits the inductance and capacitance of the printed circuit board conductors become significant circuit elements, usually undesired ; but they can be used as a deliberate part of the circuit design, obviating the need for additional discrete components.

The value associated with the card can be accessed using a magnetic stripe embedded in the card, on which the card number is encoded ; using radio-frequency identification ( RFID ); or by entering a code number, printed on the card, into a telephone or other numeric keypad.

It would be very difficult to adapt circuit-board techniques adequate at 75 MHz processor speed to meet the time-delay, power consumption, and radio-frequency interference standards required at gigahertz-range clock speeds.

Given all of these parameters, the result is a mostly-continuous analog signal which can be modulated onto a radio-frequency carrier and transmitted through an antenna.

More recently, patented advancements in SOS processing and design have been made by Peregrine Semiconductor, allowing SOS to be commercialized in high-volume for high-performance radio-frequency ( RF ) applications.

Both radio-frequency and direct-current glow discharges can be operated in pulsed mode, where the potential is turned on and off.

This non-equilibrium magnetisation can be induced, generally by applying a pulse of resonant radio-frequency close to the Larmor frequency of the nuclear spins.

Effective radio-frequency communications over such long distances over hostile radio paths require that special attention be paid to the rate at which data is repeated and error correction.

In a triode radio-frequency ( RF ) amplifier, if both the plate ( anode ) and grid are connected to resonant circuits tuned to the same frequency, stray capacitive coupling between the grid and the plate will cause the amplifier to go into oscillation if the stage gain is much more than unity.

The use of spark gap technology quickly disappeared as the more efficient continuous wave system of generating radio-frequency energy and transmitting Morse Code became standard.

At extra-high voltages ( more than 300 kV ) in outdoor buses, corona around the connections becomes a source of radio-frequency interference and power loss, so connection fittings designed for these voltages are used.