Inertia of freely mounted gyroscopes {guidance system}| preserves space orientation and so moving-object coordinates. Computers can use the reference coordinates to control object position and motion in space.
Machines {pacemaker device}| can be implants near heart and provide regular signals to heart muscles, helping ensure regular heartbeats.
In particle accelerators, chambers {resonator}| have oscillating electromagnetic fields to accelerate particles.
At automatic telephone exchanges {switchboard}|, dial signals activate switches that create a circuit between dialing and dialed telephones. At manual telephone exchanges, operator operates switches.
Machines {teletype}| can receive electronic signals and type automatically, and can send electronic signals after people type.
Electronic devices {amplifier}| {vacuum tube} {electron tube} can increase electric current.
tube
Vacuum tubes have a cathode emitter, anode collector, and zero to three positively charged screens. As it heats, cathode emits electrons {thermionic emission, amplifier}. Anode attracts electrons. Electric current flows from cathode to anode. Positive-charge electrodes {grid, vacuum tube} between cathode and anode attract electrons, to increase signal strength. Electric-signal wave frequencies do not change. Only amplitude increases.
solid state
Solid state transistor amplifiers have negative electrode transmitter and positive cathode collector, with positive electrode base between them. Current flows from transmitter to collector, as base attracts electrons, amplifying current.
The same vacuum tube or transistor {regenerative receiver}| can amplify an electric signal many times.
When ultraviolet light strikes a metal plate {ionizer}|, electrons leave and can ionize other molecules. Alps Mountains and radioactive spas naturally have negative ions. People suppose that negative ions promote health, and positive ions result in fatigue, headache, dizziness, and respiratory problems.
Cells {solar cell}| can have materials that transform light into electricity directly, with ten percent efficiency. Solar cells cannot store energy.
Alarms {burglar alarm} can use ultraviolet light, which reflects from windows and doors. If reflectors move, light-path interruption sounds alarm.
Door sensors {electric eye}| can use a collimated light source on one side and a vacuum tube {phototube} on other side. Tube has a half-cylinder plate {cathode, electric eye} that emits electrons when light hits. Electrons travel to other electrode {anode, electric eye}. Breaking light path signals a relay to open door.
Lasers {maser}| can use microwaves.
cathode-ray tube, or filmed TV program {kinescope}.
In an old process {orthicon}|, light hits a surface to emit electrons, electrons focus on a target, and target emits electrons that carry image signal from camera to television set.
Machines {radar}| can use a magnetron to emit radio waves and then receive wave reflections, to determine speed and position by Doppler effect.
Antennas {radio frequency identification tags}| (RFID) attached to circuits can activate by magnetism or radio waves. RFID are in tollbooth signalers and security systems, to identify. In low-frequency systems activated by magnetism, circuit resistance becomes high or low by turning transistor on and off, generating a magnetic field in tag {load modulation}. In high-frequency systems activated by radio waves, turning transistor on and off causes tag dipole antenna to reflect or absorb radio waves {backscatter modulation}.
Receivers {radio, machine}| can convert electromagnetic radio waves with frequency range near 10^-6 Hz to electric current. Radio waves carry sound information in frequency modulation (FM) or amplitude modulation (AM). An adjustable LC circuit {tuner} selects radio-station frequency. A circuit {filter, electronic} removes radio-station carrier frequency and leaves sound vibrations that ride on carrier wave {demodulation}. A tube or transistor amplifier increases amplitude. Speakers change electric current into sound, by vibrating an inductance coil attached to a paper cone.
Devices {television}| can display pictures and sound.
parts
A glass vacuum cathode-ray tube has an electron emitter {electron gun} at pointed end and a flat front surface coated by chemicals {phosphor} that glow after being struck by electrons.
scanning
Electromagnets outside tube direct electron paths horizontally and vertically. A single electron beam moves row by row across screen and covers whole screen once every 1/30th second.
brightness
A positive electrode controls electron stream from electron gun. Beam can be more or less to make picture lighter or darker {brightness control}. Another positive electrode {contrast control} controls difference between light and dark areas.
controls
Side electromagnets can shift picture horizontally {horizontal control} or vertically {vertical control}.
synchronization
TV signals contain synchronizing signals, so TV cameras and home TVs sweep scene at same rate. TV sound is broadcast separately from picture on FM radio.
frequency
TV has higher frequencies than radio: very high frequency (VHF) or ultra high frequency (UHF).
Elograph (George Samuel Hurst) had electrically sensing coordinates on a computer screen {touch screen}| [1971]. Screens later had a transparent surface [1974]. Today, screens use five-wire resistive [1977], surface acoustic wave, or capacitive technology.
To make images {vidicon}|, an electron beam can scan an image to find point intensities.
Small speakers {earphone, speaker}| have electric-current waves that vibrate a thin plastic disc using piezoelectricity.
Receivers {microphone}| can change sound to electric current. In some microphones {ceramic microphone}, sound pressure makes voltage in a crystal {piezoelectric effect}. In some microphones {dynamic microphone}, sound pressure moves a magnet unidirectionally or omnidirectionally in a magnetic field.
Dropping a nickel into a machine {nickelodeon}| can select a record, put it on a record player, and start the record player.
To make sound-system media {records}, microphones can detect sound and make voltage changes that cause a pointed needle to vibrate sideways and cut a plastic disc {recording music}. Plastic discs are soft wax-like material and turn like a record as needle vibrates. Signals can make larger groove widths for high frequencies and smaller groove widths for low frequencies. Machine uses plastic disc to make a metal mold {master}. A press pushes soft vinyl into mold to make a disc.
TV remote controls {remote control}| use ultrasound tuning forks at 40,000 Hz. TVs have a microphone to convert sound waves to electric-current waves.
Machines {sonar, detector}| can emit sound waves and receive wave reflections, to determine speed and position by Doppler effect.
Electric voltage and current waves can go to a solenoid connected to a paper cone {speaker, electronics}|. Waves vibrate solenoid, and vibrations vibrate paper cone to generate sound. Speakers {bass reflex speaker} can have compartments, with a hole to outside. Speakers {air suspension speaker} can be airtight. Speakers {reflecting speaker} can send sound straight in front and reflect sound off walls. Speakers can be for bass {woofer}, middle {mid-range}, and high {tweeter} frequencies.
Telephone speakers {squawk box}| can be on trading floors to alert brokers.
To record sound {stereo system}| with spatial effects, two microphones, two meters apart, record on two tracks. Two speakers, two meters apart, play back sounds recorded by microphones. Input signal can come from record-player vibrating needle, laser light reflecting from CD, or changing magnetic field from tape-recorder tape head.
Cellulose acetate or Mylar ribbon {videotape} {audiotape} has an iron-oxide or cobalt-oxide coating. Ribbon passes over an electromagnet {magnetic head} {head, tape recorder}, of size 10^-3 square inches, at 1 7/8, 3 3/4, 7 1/2, or 15 inches per second. Recording head uses magnetic field to change coating magnetism pattern on tape {tape recorder}|. Tape magnetism pattern induces a magnetic field in receiving head, which makes an electric current. Demagnetizing heads use a random magnetic field to erase tape.
Devices {telephone}| can receive and transmit human speech sounds. After two telephones are on a circuit, direct current from telephone-central-office batteries flows through circuit.
microphone
Microphones {mouthpiece, telephone} can be a round box filled with powdered carbon, covered by a flexible diaphragm. Sound compresses diaphragm and carbon, to change carbon electrical resistance and make waves in electric direct current.
speaker
Speakers {earphone, telephone} can have an electromagnet and metal diaphragm, which current waves vibrate.
wire
Telephones use three wires: one to electrical ground, one for telephone line, and one for ringing line.
dialing
Dialing telephones activates relay switches that select correct wire pair to connect to dialing telephone. Dialing then activates ringing circuit. When other telephone answers, telephone-line circuit is complete. If other telephone line is already in use, the dialing process sends a busy signal.
People talk and listen at a telephone combined microphone and speaker {receiver, telephone}.
Compression algorithms {vocoder}| {voder} can make voice sounds into coded signals.
Calculators {calculator}| {electronic calculator} can be for adding, subtracting, multiplying, dividing, and other algorithms. Electronic calculators store binary numbers in diodes in electric circuits. Arithmetic operations select different circuits to process signals.
Calculators use a metal-oxide semiconductor chip with 28 terminals, four for keyboard, eight for display, eleven for scan lines, one for clock, and three for power.
A timing mechanism at 250,000 cycles per second synchronizes input from display and keyboard, using scan lines. Diodes and keyboard functions can only activate if scan line is on.
Programs can control switching devices {computer}|. Computers are general symbol manipulator.
parts
Computers have a clock, display or printer, registers, adder-subtractor, controller, and program reader. Registers are for display, operand, accumulator, flag, address, and instructions.
functions
Computers have memory, workspace for results {accumulator}, workspace for instructions {instruction register}, arithmetic functions, functions for moving data to and from memory, and logical functions. Computers {von Neumann machine} can perform serial operations using functions, instructions, and accumulator. Serial von Neumann machines can simulate parallel operations, and vice versa.
Machines can duplicate critical functions, have self-repairing abilities, use distributed processing, have independent modules with limited interactions, and use a hierarchy from low-level functions to one high-level function.
error
Computers can have failures {glitch} with unknown causes, usually in flip-flop circuits. Computers can fail to work {down, computer}.
process
Computers can receive physical stimuli and code, store, retrieve, and transform information {computation} {information processing}. Storing and transferring algorithms have timed steps in sequence, typically with logical branches. Algorithms typically have "IF A, THEN B" statements. Computer determines if A is true and then performs B. Algorithms typically have loops: FOR i FROM m TO n, DO x. If value of i is between m and n, computer performs x. That operation changes i. Then computer checks value of i again. Algorithms perform reasoning, mathematical operations, and language processing. They can output information as scripts, images, lists, or tables.
coding
Digital computers typically store and transfer information as positions that can have one of two states {binary coding}.
Computers {digital computer}| can use electronic circuits to perform algorithms on numbers, using electrical binary codes to represent numbers and logical operations. ENIAC was first digital computer [1946].
Computers can perform more than one process simultaneously {hybrid technology multithreaded}| (HTMT).
Entangling many particle states allows solving factoring and other iterative problems {quantum computing}|. Light or particle wave superposition and interference can extract features, as in holograms and database queries.
topology
Topological quantum computing involves topological qubits. Paired excitations in a two-dimensional electron gas {anyon} have world lines that can braid to change topological properties. Knot invariants and quantum two-dimensional surface evolution over time are equivalent. In three dimensions, particles must be fermions, whose wave functions invert when fermion pairs interchange, or bosons, whose wave functions do not change when boson pairs interchange. In two dimensions, particle wave functions can show complex phases when particle pairs interchange. Spin interchanges can be clockwise or counterclockwise. If interchange results in same state, change is Abelian. Topological quantum computing must be non-Abelian to make distinct braids.
Thermal effects can create extra anyons, so temperature must be near 0 K. Larger computers can keep anyon pairs farther apart and at longer distances, to reduce spurious interactions.
Nanometer-size semiconductor crystals {quantum dot}| can change size or properties.
Memories {read-only memory}| (ROM) can stay constant and be only for input.
timer {totalizer}|.
Code in cables can be in a large frequency range {broadband}|.
Two nearby wires can exchange signals {cross talk}|.
Demagnetizing {degaussing}| randomly aligns magnetic fields.
Amplifiers can increase current or voltage {gain}|.
Sound systems can have less than 15% distortion {high fidelity}| {hi fi}.
Interfaces between metal and semiconductor have resistance {Schottky barrier}|, when voltage forces electrons into semiconductor from wire.
Code can be in a large frequency range {wideband}|. Systems {wideband code-division multiple-access} (WCDMA) can divide code into streams and send directional signals.
Wireless transmission {wi-fi}| can be digital.
Broadband information channels {wireless broadband}| can carry megabytes of information per second. Wireless uses 802.11 technology.
Signal channels can have different-wavelength signals {multiplexing, electronics}.
Two radio signals at different frequencies can mix to make a beat frequency {heterodyne}|, for amplitude modulation.
Edwin Armstrong [1918] invented a Supersonic Heterodyne Receiver to convert a selected radio frequency, for amplification and filtering {superheterodyne}| {superhet}.
Optical channels can have different-wavelength signals {wave division multiplexing}| (WDM).
Electronic number displays {field-effect liquid crystal}| can use crystals that are transparent or opaque if unpolarized or polarized by applied electric field.
Electronic number displays {interferometric modulator}| (IMOD) can use two mirrors that can vary separation and so cause constructive interference at one color.
Microscopic wires {nanowire}| can be erbium silicide or titanium. A right-left wire layer can be over an up-down wire layer {cross bar memory}. At intersections is a rotaxane monolayer, which changes resistance at high positive or negative voltage, used to write memory, and maintains resistance at intermediate voltages, used to read memory. Nanowires can make field-effect transistors. Silver-sulfide ions can act as switches. Ferroelectric thin films can move defects. Molecules can make transistors for single electrons. Nanowires can oxidize and reduce.
Wires guide electric waves, and optical fibers {waveguide}| can guide light waves.
Small silicon wafers {chip} {integrated circuit}| can have etched circuits of semiconductor transistors, resisters, capacitors, and diodes. Number of transistors doubles every one and a half to two years {Moore's Law}.
Integrated circuits {application-specific integrated circuit}| (ASIC) can have fixed logic blocks programmed in one configuration.
Light processing {digital light processing}| (DLP) can use a chip with thousands of micromirrors, to deflect colored light from a spinning color wheel.
Integrated circuits {field-programmable gate array}| (FPGA) can have programmable logic blocks.
Machines {microelectromechanical system} (MEMS) can have small mechanical and electronic parts. Silicon cells can move surfaces electrically.
Transistors {nanofluidic transistor}| can control ion flow in microscopic silica tubes.
Boards {printed circuit}| can have copper conducting pathways on one side and holes into which to solder circuit elements to conductor on other side. Film emulsion can cover board, negative of desired pattern goes on, camera photographs board, and negative develops. Silver is on conductor pathways. Electroplating puts copper on board.
Board can have a copper layer and a film emulsion that resists acid. Negative goes on, camera photographs board, and negative develops. Acid etches copper away. Then emulsion washes away, leaving copper pathways.
Memory and logic can be on same chip {processor-in-memory}|.
Chips {thin-film integrated circuit}| can have small lasers, prisms, lenses, and switches to move light instead of electrons. More information can travel in light than in electrons, because light frequency is 10,000 greater than electron current frequency.
Materials {sink}| can absorb heat or electrons. Kitchens and bathrooms have basins to receive running water.
Large metal masses {heat sink}| can absorb heat.
vacuum tube or transistor {triode}|.
Electronic number displays can use small cathode-ray tubes {vacuum fluorescent tube}|.
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Description of Outline of Knowledge Database
Date Modified: 2022.0225