What is Protection: Definition and 134 Discussions

Protection is any measure taken to guard a thing against damage caused by outside forces. Protection can be provided to physical objects, including organisms, to systems, and to intangible things like civil and political rights. Although the mechanisms for providing protection vary widely, the basic meaning of the term remains the same. This is illustrated by an explanation found in a manual on electrical wiring:

The meaning of the word protection, as used in the electrical industry, is no different to that in everyday use. People protect themselves against personal or financial loss by means of insurance and from injury or discomfort by the use of protective clothing. They further protect their property by the installation of security measures such as locks and/or alarm systems.
Some kind of protection is a characteristic of all life, as living things have evolved at least some protective mechanisms to counter damaging environmental phenomena, such as ultraviolet light. Biological membranes such as bark on trees and skin on animals offer protection from various threats, with skin playing a key role in protecting organisms against pathogens and excessive water loss. Additional structures like scales and hair offer further protection from the elements and from predators, with some animals having features such as spines or camouflage serving exclusively as anti-predator adaptations. Many animals supplement the protection afforded by their physiology by burrowing or otherwise adopting habitats or behaviors that insulate them from potential sources of harm. Humans originally began wearing clothing and building shelters in prehistoric times for protection from the elements. Both humans and animals are also often concerned with the protection of others, with adult animals being particularly inclined to seek to protect their young from elements of nature and from predators.
In the human sphere of activity, the concept of protection has been extended to nonliving objects, including technological systems such as computers, and to intangible things such as intellectual property, beliefs, and economic systems. Humans seek to protect locations of historical and cultural significance through historic preservation efforts, and are also concerned with protecting the environment from damage caused by human activity, and with protecting the Earth as a whole from potentially harmful objects from space.

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  1. F

    Differential Protection for transformer

    Hi just wondering does differential protection protect against turn to turn faults? Does it protect against all phase to phase faults or is there special circumstances where it won't protect the transformer?
  2. T

    Is Kevlar the Right Choice for Protecting Auto Fuel Tanks and Batteries?

    Would Kevlar work in protecting a rear mounted auto fuel tank from being penetrated during a rear impact (such a covering a Jeep Grand Cherokee Fuel Tank with Kevlar fabric or Kevlar Sheet)? How about protecting the floor pan mounted Lithium Ion Batteries in a Telsa S Sedan (I would need about...
  3. Artlav

    Li-ion protection breakdown voltage?

    Li-ion cells come with undervoltage protection circuits - little integrated thingies that open up the circuit when the voltage across the cell drops below 2.7V or so. What sort of a switch is that? I've been thinking, if a cell is inside a large series pack - a dozen of cells for a hobbyist...
  4. D

    Jet-engine Bird Strike Protection

    Every time I see news of a bird killing a jet engine I immediately wonder why some sort of screen cannot be placed over its inlet to either catch the bird or at least dice it into small pieces. Why is this not possible?
  5. S

    Time-reversal symmetry protection

    Hi there! I'm a third-grade physics student and I'm trying to understand the physics of topological insulators, I have found this thread, where somebody else has already asked this question, but in that thread it wasn't really answered in details, they concentrated on other issues. My...
  6. I_am_learning

    What is HIGHSET differential protection?

    I know biased differential protection system. But one differential relay I have at work here has a feature called "Differential instantaneous highset overcurrent protection". Does anyone knows anything about it?
  7. F

    Power Systems protection - how are modern relays connected

    Hi, I have a PS&P assignment where we are designing the protection for a substation - its an overview of the type of protection etc. I have a star delta 42MVA (cyclic rating) 132:22 kv TX... I've done some research and want to use an SEL487E relay. Since this is star delta (star...
  8. T

    Gear Noise Protection - Getriebekapselung

    Hello, I'm a technical translator from Germany and urgently looking for a particular term: It describes a kind of case/protection around the gearbox which reduces noise emission. The German term is "Getriebekapselung" ("getriebe" = gear, kapselung = "protection/case/capsule?" Is...
  9. F

    Reverse polarity protection circuit. Help with component values?

    EE is not my forte. Although this little circuit is so simple that I could get myself 90 percent there, it performs such an important function that I would like to get it more like 99 percent correct. I want to add the circuit to this board...
  10. P

    Lightning Protection Systems: Direct vs Indirect Strokes & EMPs

    About two weeks ago, I wanted to find out more about the design of lightning protection systems. In particular, I wanted to figure out what gage of wire would be necessary for linking a lightning rod to earth-ground. What I had learned is that the gage of the wire would have to be extremely...
  11. M

    How can I add overload protection to my current limit circuit?

    Hi, I made a current limit protection circuit at 1A, and I would like to improve it with an overload protection. Could you give me please some ideas how to switch off the mosfet when the load current exceed 1A? Thank you
  12. J

    DC Reverse polarity protection using P-MOSFET

    Hello All, I'm designing a circuit board that needs to run on a 12VDC supply and will need to supply a fair amount of power to drive a bunch of 12V relay coils, in addition to some electronics. Since I want to keep the voltage drop on the supply a small as possible, I thought about using a...
  13. E

    Doubt on snubber circuit for an scr for dv/dt protection

    The main aim of turning on/off an scr is to disconnect source from load. I read in dv/dt protection of scr using snubber circuit, the scr may turn on when dV/dt is very high as the charging current i=cdV/dt will be high enough to turn on scr. So we are using a snubber circuit to divert this high...
  14. D

    News Explore the Impact of Grover Norquist's Taxpayer Protection Pledge

    Well, I've never started a political thread on the boards before, nor do I usually get involved in politics because of its persistently unscientific nature, but I feel this topic is of the most profound significance and thus a VERY worthy and eminent discussion. Many in the know would say that...
  15. R

    Output short protection circuit

    I am making a totem pole digital output of 1.5-23v. i was searching for a protection circuit for the output short to ground and +24v dc. please help me out by sending a diagram of the circuit if possible.
  16. G

    MEM protection of carbohydrates

    Would this work? I can't seem to find any examples in Scifinder of carbohydrates where all the -OH groups are protected with either MEM or MOM. Is there a reason why? Will this not work? I know using MEM and MOM are pretty standard for protecting alcohols, why in the case of carbohydrates...
  17. D

    MHB What causes the formation of a spiral pattern in fluids?

    https://www.physicsforums.com/attachments/168
  18. J

    Galvanic protection of multiple materials maintaining electric connection

    I am looking for the best way to prevent corrosion between two different materials while maintaining electrical contact between them. Specifically, I am wondering about carbon fiber panels placed on an aluminum base and exposed to seawater. Carbon (graphite at least) has a much higher galvanic...
  19. S

    Sacrificial protection and how it works

    How do sacrificial metals protect the less reactive metal that it protects? Some people say that it provides the iron with electrons when it starts to rust. But if it does provide electron to the iron then the magnesium block for example will become positive ions. But then how can the magnesium...
  20. D

    Which RS232 Protection Circuit is Better: RS232_Protect_1 or RS232_Protect_2?

    I have attached two different schematics of circuits that I thought would be capable of protecting RS232 signals. The second one (RS232_Protect_2) I feel is all I would need to protect the RS232 chip from any mayhem that may occur on the actual device side. But, someone referred me to the...
  21. C

    Why does my laptop freeze when I shake it while watching a movie?

    My laptop is equipped with hard drive shock protection. If I am watching a movie and the accelerometer senses a perturbation (me shaking the computer) the image is immediately frozen, but there is no interruption in the sound. Why is this the case?
  22. I

    Surge protector for EMI protection in place of EMI filter

    can i use surge protector for EMI protection inplace of EMI filter?what the difference between them?
  23. B

    Grounding Terminal In Electrical Plugs: Protection or Risk?

    What is the purpose of the grounding terminal in the plugs of some electrical appliances? Is it designed to act as an arrestor for unwanted electrical charge coming from lightning, static electricity, power fluctuations, and electrical arcs, sending the excess current to a grounding wire...
  24. Q

    What does it mean by : 'Fire and explosion protection on offshore platforms'

    just a project i have to start working on soon wanted to know if i can get any useful information about it please thanks
  25. S

    TVS Diodes for ESD Protection?

    I'm developing a basic cable continuity tester. Essentially, the circuit drives a test vector onto the cable and reads back the output vector. The output has MOSFETs for buffers/drivers but the input is connected directly to the ICs (CPLD, in my case). My concern is ESD. Unfortunately, I have...
  26. W

    Earthing & Lightening Protection for a Home on a Mountain Top

    G'Day guys, We have been looking around and feel this would be an appropriate forum full of good knowledgeable people to ask a few challenging questions. The missus an I are about to build a house on a mountain top that is the highest peak for at least 1-2 km's (1 mile or more). Obviously...
  27. M

    Circuit Breaker Ratings and Electrical Protection

    Hi, I am student electrical engineer and I should probably know this stuff but I am trying to work out how to determine the required short circuit current rating of circuit breaker, I have seen in the Schneider Electric catalog 'determination of short-circuit current" using cable data and...
  28. B

    Help with prototype-circuit protection

    Hello. First off, I am not an electrical engineer, have no college education, just an inventive mind, and smart enough to get myself into trouble. The project: I have a automotive computer I need circuit protection for. This computer draws a maximum of 30 (dual 15 amp fuses) amps at 12 VDC on...
  29. A

    Distance Protection: Why Preferable for Medium & Long TLs?

    Why Distance( Impedance) protection is always preffered in the Transmission Lines protection? As for as Short TL is concern, Sometimes we use distance as well as differential protection, but in Medium and Long Transmission Lines only Distance protection is used .. why is it so? what's the...
  30. A

    Back E.M.F Protection: Selecting Diodes & Surge Suppression

    Help me. I want to use diode for back E.M.F protection.Please help me to select diode which is suitable ,like short circuit recovery time is 9 nano second and ifsm should be 30-90 amp. please also send me surge suppression protection circuit or surge protection device.
  31. S

    I designing an overload protection circuit

    so I am creating a simple electric motor and I need a circuit that will cut the power if it is stalled (since it can create a short if it is stalled, draining/damaging the batteries) - the problem is that it also creates a short for a small period of time while in regular use I would like to...
  32. S

    Solar vs Conventional Inverters: Exploring Protection Devices

    How does solar inverter differ from conventional inverters? And what are the various protection devices inside the solar inverter?
  33. Astronuc

    Radiation protection/ effects of radiation

    FYI - Consolidated Guidance: 10 CFR Part 20 — Standards for Protection Against Radiation (NUREG-1736) http://www.nrc.gov/reading-rm/doc-collections/nuregs/staff/sr1736/ I expect there are lots of questions about radiation effects and radation protection. So please post questions or...
  34. E

    Do wooden wall or window glass give good protection from penetrating radiation

    Do wooden wall or window glass give good protection from penetrating radiation such as gamma rays?
  35. K

    Help: protection of an orchard from frost by burning tires

    I found this question in a book about physics, but there was no explanation. Q: Why do fruit fruit growers set car tires on fire in their orchards in the clear winter mornings? I imagine te answer would be to stop frost from forming, but I don't understand how smoke or soot could do that. The...
  36. G

    Protection from both beta particles & Gamma rays?

    What would be the best protection from these two at the same time? Lead alone or a mixture of something like lead and Plexiglas?
  37. T

    Finding a TVS Diode for 137mV Back EMF Protection

    Hey, I'm trying to find a suitable diode to protect against some back EMF in my circuit, but I don't know much about them and so I'm having a really hard time finding one. If someone could look at what i need and then possibly send me a link i'd be so grateful. Requirements: back EMF = 137mV...
  38. L

    How Transmission Lines Transposition could affect Protection systems?

    I would like to know if Transposition on Transmission Lines could affect the basis and the way the power system is evaluated to set up the protection for the Transmission line? as compared to the non-transposed Transmission Lines. Thanks in advance, Regards,
  39. K

    Buoyant Force and Massive G force protection?

    I am interested in determining if a method can be devised to create a safe zone for humans to be accelerated at very high G force. I watched a very interesting experiment where a water filled balloon was submerged in container of water and had 60 g's of force applied via a centrifuge. The...
  40. T

    The Great Egg Drop Contest: Design a Protection Device

    An egg is hard, but yet delicate food that people have been making contests of, for many years. But i am part of one that i lack the physics to figure out the perfect device here are the simple rules of this contest. Holy Omelets Batman… It’s the Egg Drop Contest! Design a egg protection...
  41. T

    Ok to use MOSFET body diode as flyback protection?

    Hello, I am designing a motor controller, and I was curious about the MOSFETs I'm using that have an internal body diode zener for Vds protection that is common in a lot of datasheets. I am switching the coils of the inductor with these MOSFETs, and I would like to know if its unwise to...
  42. L

    Why lead can be used for protection ?

    Hi all, anybody knows why x-ray cannot penetrate into a sheet of lead paper deeply? Do only the big amount of electrons in lead atoms diffract the x-ray, or the protons in the atoms also contribute the diffraction ? Thank you for your time!
  43. mugaliens

    Patent Protection vs Prevention - Where Falls the Line of Intellectual Property?

    This from another thread (according to PF's rules, the quoted part belongs in that thread, but the follow-on part belongs in its own, separate thread): So: mheslep, yours is a very good reminder that market economies will render whatever new technologies at least as expensive as any...
  44. G

    Overcurrent Protection: Prevent Malfunctioning Loads & High Efficiency

    I need to prevent a malfunctioning load from drawing too much current from a supply of around 3Vdc@2A(max). There is already a current sensor in series with the load which outputs a voltage, Vsense, proportional to the current drawn by the load. I was thinking a PMOS switch with the gate tied...
  45. S

    CT for restricted earth fault (REF) protection

    Does somebody could advice me, whether the nominal primary CT to be used for REF protection must be same? The CT I have now as follow: Power Transformer: 60MVA, 150/20kV, Ynyn(0)d1 CT on 20kV switchgear 2000/5, class 5P20 CT on neutral Power Transformer: 1200/5, class X Relay to be used...
  46. A

    Protection of car from thndrstrom

    why you are safe inside a metal car during a thunderstrom?
  47. J

    Generator loss of exitation protection

    I am trying to protect a generator fro loss of field with a reverse KVAR relay. My question is does a reverse KVAR relay's current transformer need to be upstream or downstream of AVR's connection to line voltage? (AVR is automatic voltage regulator) Does it matter at all.
  48. J

    Paralleled Generator Protection

    What is the difference between a reverse power relay and a reverse KVAR relay?
  49. S

    DC motor start-up surge is tripping the battery protection circuit - help

    Hi all, I've got a problem which is so daft it hurts. I'm using lithium batteries, and I'm well aware of the dangers, so despite being fine with working on an un-protected cell, I changed to protected ones, and then issues appeared. The current is drawn from a pair of parallel 18650's...
  50. V

    Surge Protection for 24V DC Input Circuit

    I had a circuit of buck convertor that converting 24V dc to 4V dc. 24V dc input is from a PSU (Meanwell's PLN series), once it go in, it connects to a Polyfuse, then polarity diode (in series), then Common mode choke, then it's my converter's input capacitor (35V 47uF AVX's TAJ series)...
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