Quantum Oscillations - Brown University Wiki
... In a pure or “intrinsic” semiconductor, electrons can only occupy states within the allowed bands of the material. However, many semiconducting materials are doped with impurities that reduce the energy required for electrons to enter the conduction band. These are “extrinsic semiconductors”. There ...
... In a pure or “intrinsic” semiconductor, electrons can only occupy states within the allowed bands of the material. However, many semiconducting materials are doped with impurities that reduce the energy required for electrons to enter the conduction band. These are “extrinsic semiconductors”. There ...
UW- Madison Geology 777
... Faraday cups. This is a small cup that sits just outside of the central axis of the column, and can be swung in to intercept the beam upon automated control. This is typically done at the end of each measurement on both standards and unknowns, and using these values, the measured X-ray counts are no ...
... Faraday cups. This is a small cup that sits just outside of the central axis of the column, and can be swung in to intercept the beam upon automated control. This is typically done at the end of each measurement on both standards and unknowns, and using these values, the measured X-ray counts are no ...
Medical Instrumentation Application Lecture #1
... • No. of conduction electrons can be controlled by the no. of impurity atoms. By controlling the doping amount, virtually any resistance can be achieved. ...
... • No. of conduction electrons can be controlled by the no. of impurity atoms. By controlling the doping amount, virtually any resistance can be achieved. ...
Voltage Controlled Oscillator
... The voltage controlled oscillator (VCO) generates a clock with a controllable frequency. The VCO is commonly used for clock generation in phase lock loop circuits, as described later in this chapter. The clock may vary typically +/-50% of its central frequency. A current-starved voltage controlled o ...
... The voltage controlled oscillator (VCO) generates a clock with a controllable frequency. The VCO is commonly used for clock generation in phase lock loop circuits, as described later in this chapter. The clock may vary typically +/-50% of its central frequency. A current-starved voltage controlled o ...
Transferred Electron Devices (TEDs)
... the bulk negative-resistance property of uniform semiconductors rather than from the junction negative-resistance property between two different semiconductors, as in the tunnel diode. ...
... the bulk negative-resistance property of uniform semiconductors rather than from the junction negative-resistance property between two different semiconductors, as in the tunnel diode. ...
Cavity magnetron
The cavity magnetron is a high-powered vacuum tube that generates microwaves using the interaction of a stream of electrons with a magnetic field while moving past a series of open metal cavities (cavity resonators). Bunches of electrons passing by the openings to the cavities excite radio wave oscillations in the cavity, much as a guitar's strings excite sound in its sound box. The frequency of the microwaves produced, the resonant frequency, is determined by the cavities' physical dimensions. Unlike other microwave tubes, such as the klystron and traveling-wave tube (TWT), the magnetron cannot function as an amplifier, increasing the power of an applied microwave signal, it serves solely as an oscillator, generating a microwave signal from direct current power supplied to the tube.The first form of magnetron tube, the split-anode magnetron, was invented by Albert Hull in 1920, but it wasn't capable of high frequencies and was little used. Similar devices were experimented with by many teams through the 1920s and 30s. On November 27, 1935, Hans Erich Hollmann applied for a patent for the first multiple cavities magnetron, which he received on July 12, 1938, but the more stable klystron was preferred for most German radars during World War II. The cavity magnetron tube was later improved by John Randall and Harry Boot in 1940 at the University of Birmingham, England. The high power of pulses from their device made centimeter-band radar practical for the Allies of World War II, with shorter wavelength radars allowing detection of smaller objects from smaller antennas. The compact cavity magnetron tube drastically reduced the size of radar sets so that they could be installed in anti-submarine aircraft and escort ships.In the post-war era the magnetron became less widely used in the radar role. This was because the magnetron's output changes from pulse to pulse, both in frequency and phase. This makes the signal unsuitable for pulse-to-pulse comparisons, which is widely used for detecting and removing ""clutter"" from the radar display. The magnetron remains in use in some radars, but has become much more common as a low-cost microwave source for microwave ovens. In this form, approximately one billion magnetrons are in use today.