User:John R. Brews

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I am a Professor Emeritus of Electrical Engineering from The University of Arizona, where I taught device physics and circuit design for just under two decades. Previously, I was a research scientist for twenty-odd years at Bell Laboratories, Murray Hill, doing theoretical work in the areas of solid-state physics and device physics. I also am a Fellow of the IEEE, and a recipient of the Electron Device Society distinguished service award for work as Editor-in-chief of the journal IEEE Electron Device Letters, founded by Nobel prize winner George E. Smith. I've published a number of technical books and papers, some of which may be found at this link.

Images

Magnetism

(CC) Image: John R. Brews B-field lines near uniformly magnetized sphere     (CC) Image: John R. Brews Magnetic flux density vs. magnetic field in steel and iron

Widlar current source

(CC) Image: John R. Brews Widlar current source using bipolar transistors     (CC) Image: John R. Brews Small-signal circuit for finding output resistance of the Widlar source     (CC) Image: John R. Brews Design trade-off between output resistance and output current in Widlar source

Forces

(CC) Image: John R. Brews Force and its equivalent force and couple     (PD) Image: John R. Brews Centripetal force FC upon an object held in circular motion by a string of length R. The string is under tension FT, as shown separately to the left.     (PD) Image: John R. Brews Upper panel: Ball on a banked circular track moving with constant speed v; Lower panel: Forces on the ball.     (PD) Image: John R. Brews Polar unit vectors at two times t and t + dt for a particle with trajectory r ( t ); on the left the unit vectors uρ and uθ at the two times are moved so their tails all meet, and are shown to trace an arc of a unit radius circle.     (PD) Image: John R. Brews Local coordinate system for planar motion on a curve.

Electromagnetism

(CC) Image: John R. Brews Electric motor using a current loop in a magnetic flux density, labeled B

Devices

(PD) Image: John R. Brews Cross section of MOS capacitor showing charge layers     (PD) Image: John R. Brews Three types of MOS capacitance vs. voltage curves. VTH = threshold, VFB = flatbands      (PD) Image: John R. Brews Small-signal equivalent circuit of the MOS capacitor in inversion with a single trap level     (PD) Image: John R. Brews A modern MOSFET     (PD) Image: John R. Brews A power MOSFET; source and body share a contact.     (CC) Image: John R. Brews Calculated density of states for crystalline silicon.     (CC) Image: John R. Brews Field effect: At a gate voltage above threshold a surface inversion layer of electrons forms at a semiconductor surface.     (PD) Image: John R. Brews Occupancy comparison between n-type, intrinsic and p-type semiconductors.     (PD) Image: John R. Brews Nonideal pn-diode current-voltage characteristics     (PD) Image: John R. Brews Band-bending diagram for pn-junction diode at zero applied voltage     (PD) Image: John R. Brews Band-bending for pn-diode in reverse bias     (PD) Image: John R. Brews Quasi-Fermi levels in reverse-biased pn-junction diode     (PD) Image: John R. Brews Band-bending diagram for pn-diode in forward bias     (PD) Image: John R. Brews Fermi occupancy function vs. energy departure from Fermi level in volts for three temperatures     (PD) Image: John R. Brews Fermi surface in k-space for a nearly filled band in the face-centered cubic lattice     (PD) Image: John R. Brews A constant energy surface in the silicon conduction band consists of six ellipsoids.     (PD) Image: John R. Brews Planar Schottky diode with n+-guard rings and tapered oxide.     (PD) Image: John R. Brews Comparison of Schottky and pn-diode current voltage curves.     (PD) Image: John R. Brews Schottky barrier formation on p-type semiconductor. Energies are in eV.     (PD) Image: John R. Brews Schottky diode under forward bias VF.     (PD) Image: John R. Brews Schottky diode under reverse bias VR.     (PD) Image: John R. Brews Critical electric field for breakdown versus bandgap energy in several materials.     (PD) Image: John R. Brews Schottky barrier height vs. metal electronegativity for some selected metals on n-type silicon.