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   Relays, Vacuum

A relay is an electrical switch that opens and closes under control of another electrical circuit. In the original form, the switch is operated by an electromagnet to open or close one or many sets of contacts. It was invented by Joseph Henry in 1835. Because a relay is able to control an output circuit of higher power than the input circuit, it can be considered, in a broad sense, to be a form of electrical amplifier.

These contacts can be either Normally Open (NO), Normally Closed (NC), or change-over contacts.

  • Normally-open contacts connect the circuit when the relay is activated; the circuit is disconnected when the relay is inactive. It is also called Form A contact or "make" contact. Form A contact is ideal for applications that require to switch a high-current power source from a remote device.
  • Normally-closed contacts disconnect the circuit when the relay is activated; the circuit is connected when the relay is inactive. It is also called Form B contact or "break" contact. Form B contact is ideal for applications that require the circuit to remain closed until the relay is activated.
  • Change-over contacts control two circuits: one normally-open contact and one normally-closed contact with a common terminal. It is also called Form C contact.


Bronze Partners
Aleph International Corp.
American Relays, Inc.
Amperite Co.
GIGAVAC
Jennings Technology Corp.
Master Electronic Controls (MEC)
MEDER electronic Inc.
Ross Engineering Corp.
Spectron Glass & Electronics Inc.
The Fredericks Co.
Triridge Corp.
Fixed and programmable amplifiers - Frequency Devices

 

Books
Power Vacuum Tubes Handbook, Second Edition
Jerry C. Whitaker

Excerpt - page 170: "... voltage. The table indicates the recommended location of a suitable relay that should act to remove the prin- ..."
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Vacuum Science and Technology: Pioneers of the 20th Century (AVS Classics in Vacuum Science and Technology)
Paul A. Redhead

Excerpt - page 64: "... that, due to the presence of a reservoir forming a vacuum regulator between these pumps and the mechan- ical pump, the latter functioned only intermittently under the action of a manometric relay. This practice seems to have been forgotten since. Among the ..."
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Vacuum Bazookas, Electric Rainbow Jelly, and 27 Other Saturday Science Projects.
Neil A. Downie

How to Keep Your Volkswagen Alive 19 Ed: A Manual of Step-by-Step Procedures for the Compleat Idiot
John Muir, Tosh Gregg, and Peter Aschwanden

Excerpt - page 322: "... the intake air distributor. Connect the wire to the main relay and the vacuum hose from the intake air distributor to the pressure sensor. ..."
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The Singularity Is Near: When Humans Transcend Biology
Ray Kurzweil

Excerpt - page 67: "... the figure demonstrates, there were actually four different paradigms- electromechanical, relays, vacuum tubes, and discrete transistors-that showed exponential growth in the price-performance ..."
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Code: The Hidden Language of Computer Hardware and Software
Charles Petzold

Excerpt - page 243: "... headed by Aiken taught the first classes in computer science. Relays weren't perfect devices for constructing ... for the relay is the vacuum tube, which was developed by John Ambrose Fleming (1849-1945) and ..."
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Why Things Bite Back: Technology and the Revenge of Unintended Consequences (Vintage)
Edward Tenner

Excerpt - page 351: "... many times faster than the room- and building-size arrays of relays and vacuum tubes of the industry's pioneer days. Steel is lighter and ..."
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Pattern on the Stone (Science Masters)
Daniel Hillis

Excerpt - page 107: "... early 1950s, when computers were being developed, the switching elements (relays and vacuum tubes) were expensive but relatively fast. The memory elements (mercury ..."
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Isaac Asimov: The Complete Stories, Vol. 1
Isaac Asimov

Excerpt - page 521: "... and expensive is that it has to be full of relays and vacuum tubes just so that microscopic electric currents can be controlled ..."
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Einstein's Clocks, Poincare's Maps: Empires of Time
Peter Galison

Excerpt - page 251: "... Paul (an apprentice machine technician), Einstein bandied about ideas for relays, vacuum pumps, electrometers, voltmeters, alternating cur- ..."
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Principles of Avionics, Third Edition
Albert Helfrick

Excerpt - page 243: "... fixed value capacitors and switching them in parallel with a relay, as shown in Fig. 6.10. ... prevent breakdown, the relays are vacuum-sealed. Ceramic capacitors, which do not use ambient air as a ..."
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Camaro Owner's Hp1301
Keystone Automotive - Drop Ship

Excerpt - page 97: "... installing new hoses, start at a reliable source of manifold vacuum and work forward. Install filter (arrow) near vacuum source then install tee. One hose goes to dash-mounted headlamp switch; other goes to relay on vacuum reservoir. 19. Vacuum relay on 1968-69 RS has ..."
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Fundamentals of Modern Manufacturing: Materials, Processes, and Systems, 2nd Edition
Mikell P. Groover

Excerpt - page 787: "... electronic switching systems that were more reliable than the electromechanical relays and vacuum tubes used at that time. In February 1959, I. Kilby ..."
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Philosophical Papers (Philosophical Papers/Hilary Putnam, Vol 2)
Hilary Putnam

Excerpt - page 414: "... agents to be realized as automata built out of flip-flops, relays, vacuum tubes, and so forth. But even in this last case ..."
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Nanofuture: What's Next For Nanotechnology
J. Storrs Hall

Excerpt - page 101: "... shafts and gears, as in Babbage's design, followed by electromagnetic relays, vacuum tubes, discrete transistors, integrated circuits, and a series of order-of-magnitude ..."
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The Dream Machine: J.C.R. Licklider and the Revolution That Made Computing Personal
M. Mitchell Waldrop

Excerpt - page 60: "... sort that could be built with a set of electromechanical relays or vacuum tubes. And that, if nothing else, meant that von Neumann ..."
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Data Conversion Handbook (Analog Devices)
Engineering Staff Analog Devices Inc.

Excerpt - page 149: "... SWITCHES ANALOG R OUTPUT R CIRCA 1920 R SWITCHES WERE RELAYS OR VACUUM TUBES R Figure 3.4: Simplest Voltage-Output Thermometer DAC: The Kelvin ..."
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Scientific American Inventions and Discoveries : All the Milestones in Ingenuity From the Discovery of Fire to the Invention of the Microwave Oven
Rodney Carlisle and Scientific American

Excerpt - page 413: "... a wide variety of electromechanical machines were developed that used relays, vacuum tubes, and electrical wiring to accomplish mathematical computations. Since the ..."
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Tools for Thought: The History and Future of Mind-Expanding Technology
Howard Rheingold

Excerpt - page 16: "... Just as the hardware basis for computing has evolved from relays to vacuum tubes to transistors to integrated circuits, the programs have evolved, ..."
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Reliable Computer Systems: Design and Evaluation
Daniel P. Siewiorek and Robert S. Swarz

Excerpt - Front Matter: "... age. The earliest computers were constructed of components such as relays and vacuum tubes that would fail to operate correctly as often as ..."
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Introduction To Programming with Visual Basic .net
Gary J. Bronson and David Rosenthal

Excerpt - page 40: "... computers of the 1950s, all hardware units were built using relays and vacuum tubes. The resulting computers were extremely large pieces of equipment, ..."
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Beethoven's Anvil: Music in Mind and Culture
William L. Benzon

Excerpt - page 53: "... represented and realized by various kinds of devices, including "electromechanical relays, vacuum tubes, crystal diodes, ferromagnetic cores, and transistors." Regardless of how ..."
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Body of Secrets: Anatomy of the Ultra-Secret National Security Agency
James Bamford

Excerpt - page 579: "... for codebreaking. Known as Rapid Analytical Machines (RAMs), they employed vacuum tubes, relays, high-speed electronic circuits, and photoelectrical principles. They were ..."
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Darwin Among the Machines: The Evolution of Global Intelligence (Helix Books)
George B. Dyson

Excerpt - page 39: "... timing diagrams that brought mechanical logic into the age of relays, vacuum tubes, transistors, microprocessors, and beyond. Computers have been paying their ..."
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The Internet Revolution: The Not-for-Dummies Guide to the History, Technology, and Use of the Internet
J. R. Okin

Excerpt - page 28: "... that no, or minimal, heat is given off.) Unlike a vacuum tube, the transistor produced no ... like the migration from electromechanical relays to vacuum tubes to transistors, this evolution in the technology ..."
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The Computer and the Brain: Second Edition (Mrs. Hepsa Ely Silliman Memorial Lectures)
John von Neumann

Excerpt - page 7: "... the course of the development up to now, elec- tromechanical relays, vacuum tubes, crystal diodes, 7 ..."
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Beginning Programming for Dummies
Wally Wang and Wallace Wang

Excerpt - page 55: "... as a bug. In the early days, computers used mechanical relays and vacuum tubes instead of circuit boards and microprocessors. One day, the ..."
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How We Got Here: A Slightly Irreverent History of Technology and Markets
Andy Kessler

Excerpt - page 122: "... research arm of AT&T and Western Electric, was playing with relays and vacuum tubes to do switching. All of a sudden, electronic computing ..."
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The World Treasury of Physics, Astronomy, and Mathematics: From Albert Einstein to Stephen W. Hawking and From Annie Dillard to John Updike - an Eloquent ... Collection From More Than 90 of This Centu
Timothy Ferris

Excerpt - page 481: "... In the course of the development up to now, electromechanical relays, vacuum tubes, crystal diodes, ferromagnetic cores, and transistors have been successively ..."
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Tool and Manufacturing Engineers Handbook, Vol 1 : Machining
Tom Drozda

Excerpt - page 336: "... state Pertaining to an electrical circuit having no moving parts, relays, vacuum tubes, or gaseous tube components. source language A computer input ..."
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Technician's Guide to Industrial Electronics: How to Troubleshoot and Repair Automated Equipment
Robert Carrow

Excerpt - page 70: "... and switches continue to develop faster than ever. Analytical engine Relays Vacuum tubes A 4-1 The evolution of the suritch Transistors 7 ..."
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The Age of Spiritual Machines: When Computers Exceed Human Intelligence
Ray Kurzweil

Excerpt - page 27: "... fifth paradigm since the inception of computation-after mechanical, electromechanical (i.e., relay based), vacuum tube, and discrete transistor technology-to provide accelerating returns to computation. ..."
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Before the Computer
James W. Cortada

Excerpt - page 118: "... that were not widely applied until the 1940s and 1950s (relays, vacuum tubes) or were so limited in demand that the economic ..."
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Microcosm: The Quantum Revolution In Economics And Technology
George Gilder

Excerpt - page 177: "... system for economizing on the use of expensive and unreliable relays, vacuum tubes, and other switches. Mead's experience in the microcosm , ..."
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Poem a Day, Vol. 2
Laurie Sheck

Excerpt - page 266: "... seed of the computer is to be found, the ticking relays, the vacuum tubes of the future. With charming innocence this algebra teaches ..."
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Reliability of Computer Systems and Networks: Fault Tolerance, Analysis, and Design
Martin L. Shooman

Excerpt - page 146: "... by the maintenance problems of the early computers related to relay and vacuum tube failures. A study of the Univac computer that was ..."
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