What is Switch: Definition and 563 Discussions

In electrical engineering, a switch is an electrical component that can disconnect or connect the conducting path in an electrical circuit, interrupting the electric current or diverting it from one conductor to another. The most common type of switch is an electromechanical device consisting of one or more sets of movable electrical contacts connected to external circuits. When a pair of contacts is touching current can pass between them, while when the contacts are separated no current can flow.
Switches are made in many different configurations; they may have multiple sets of contacts controlled by the same knob or actuator, and the contacts may operate simultaneously, sequentially, or alternately. A switch may be operated manually, for example, a light switch or a keyboard button, or may function as a sensing element to sense the position of a machine part, liquid level, pressure, or temperature, such as a thermostat. Many specialized forms exist, such as the toggle switch, rotary switch, mercury switch, push-button switch, reversing switch, relay, and circuit breaker. A common use is control of lighting, where multiple switches may be wired into one circuit to allow convenient control of light fixtures. Switches in high-powered circuits must have special construction to prevent destructive arcing when they are opened.

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  1. S

    Flux linking (and de-linking?)

    Initially the current is non-zero therefore we have a magnetic field present, and at the end there is no current therefore there is no magnetic field present. When we open the switch, and the current drops to 0, there is a change in the magnetic flux of B, as the field from A has gone. This...
  2. J

    How do you switch language from German to English with 8.1 knoppix usb

    Hello I'm booting from 8.1 Knoppix usb and want to switch the language settings from German to UK English but don't know how. Thanks
  3. Mufeez

    A student here who is planning to switch to Physics from zoology

    Hello there, I am Mufeez. I am currently enrolled at QAU in the field of zoology. Didn't plan to study zoology so I am gonna drop it and try to move towards my main interest that is physics. Joined PF to learn physics and get help and make connections. Hope ya'll have a good day.
  4. E

    How Is a Power Recliner Wired for Multiple Functions?

    As far as I can tell there are three circuit states that control the recliner foot rest, raise it, lower it, and off. How is this wired, how does the switch function etc...? I assume the up and down switch flip the polarity across the motor, but that is all I can seem to reason out...
  5. leVanw

    Is there a Switch that can Withstand a Very High Current?

    Is there any compact electronic component used to make a switch that can withstand large currents from a series of capacitors connected in parallel with a total voltage of over 600V?
  6. Edy56

    Calculate Vout with the switch

    TL;DR Summary: I need to calculate Vout when the switch Is closed and open. I need to calculate Vout when the switch Is closed and open. Is my work correct?
  7. A

    Linear moving switch, decade counter, chaser

    I need a row of switches, about 30 to be exact and the idea I need is to have a "moving OFF position" much the same way a "LED chaser" works where you have a moving ON position. Only unlike in a LED chaser where one diode comes ON at any given time and the positions changes continually to...
  8. W

    Troubleshooting Pneumatic Interlock Switch for Machine Safety

    I have a machine that when operator presses button, it will move upwards. When it gets to the end position, a switch is made and that causes a double acting pneumatic cylinder to engage... pushing a pin into a sort of "Dead bolt" safety position.. to lock machine in place. Operator then does...
  9. Element13

    Electronics Custom Multi Light Switch with Dimmer

    My Next DIY, So, I'm guessing something like this may already exists (see image) light bulbs added for clarification purposes only. Anyone know if there's something like this already on the market? So, I did a google search for custom toggle switches but most if not all were for Marine or...
  10. J

    Find the Capacitance based on 3 different switch positions

    You can find the impedance for each of the three positions with V/I. However I'm not sure how to find the inductive and capacitive reactance. Thanks for your help.
  11. NTL2009

    In Search of: Cheap/common pressure switch

    I'm certain these must be common in automotive applications, but I'm just not sure what search terms to use. I'm looking for an on/off switch (to be electronically sensed, so low volt/current) that can be connected to a water pipe, and turn on/off at around 1~2 PSI. The specific application...
  12. Next_Of_Kintetic

    How can I reroute multiple signals from a 4 pin connector using a relay switch?

    Hi, First off, I want to say that I'm basically a noob when it comes to electrical engineering; I have some knowledge and took an intro to robotics course in college, but if I knew the answer to this question, then I wouldn't be here asking haha. So here it is: From what I know, relay...
  13. C

    Switch Argument Outside While Loop Execution Explained

    #include<stdio.h> #define MAX_SIZE 6 int pop(int a[]); void push(int a[],int e); int pal(int a[]); int *top; int stack[MAX_SIZE]; int main(){ int choice,done=0,ele; printf("1.Push\t2.Pop\t3.Pal\t4.Exit\n"); printf("Enter your choice:\t"); scanf("%d",&choice); while(!done){...
  14. Ugnius

    RL circuit after switch has been opened

    Hi guys , I've been trying to think this one out but I'm drawing a blank. What I am able to understand that I'm required to calculate the backwards emf when the switch is opened. The current through the resistor R1 is 9mA. I was wondering if 9.2mA is even possible? Can the current exceed Imax...
  15. K

    What happens when ON/OFF switch is in the midway?

    I have a switch home that is not easy to press and sometimes if I forget to press it hard enough it will stay in the midway for a few seconds but I always push it to ON or OFF soon. Could this cause any problem to my electrical or electronics appliance?
  16. B

    Mathematically Ramp down a sinewave to 0 or switch frequencies

    How do Mathematically Ramp down a sinewave to 0 or switch frequencies without causing a clicking sound? I wrote code to play a sinewave but when I stop the sound I can hear a clicking sound. I tried to slowly ramp down the Amplitude, but that seem to only work for some Combination of...
  17. K

    What is the possible risk of switch in its mid-way?

    Sometimes, not always though, it was my problem, not the switch is defected, I didn't press it firmly, the switch will leave in its mid-way, but it is supposed to be either ON or OFF. What is the possible problem of doing this? Will it burn the switch or cause even more severe problem?
  18. E

    Why Did My Wire Burn When I Turned On the Switch?

    Hello, I am wondering why a wire that was connected from a MAIN BUS BAR to the top side of a switch and when turned ON burnt immediately and the wire connected from the bottom side of the switch to the BUS BAR needing power slowly burnt. I'm thinking the wiring was reversed- Correct me...
  19. A

    PPMT, Magnetic Flux Switch, electro-permanent magnet generator

    Ok so here is something that made me scratch my head and I still can't come to a final conclusion. The basic idea is seemingly simple. You have permanent magnets attached to a core, the field lines close on both magnets through the core, so far so good. but the core also has electromagnets , put...
  20. binbagsss

    Drop out of PhD in fluid mechanics and switch to Mres in mathematical physics?

    A post doc in an area that differs from my PhD? I am currently doing a PhD in fluid mechanics but want to do mathematical physics tbh. In another thread I got an answer about a user who had done a PhD in accelerator physics and went to do a post-doc in condensed matter, vice versa even, but in...
  21. Y

    Battery Operated Ceiling Light and Light Switch?

    Does anyone know of any products that would allow me to install a battery operated light switch and ceiling light? This would save me a lot over tearing down all the sheetrock, replacing sheetrock, painting, etc.. I'm thinking a switch with a faceplate. A simple button cell would go behind the...
  22. E

    Voltage across an inductor after flipping a switch

    When the energy of the capacitor is minimal it has no charge therefore the voltage on it is 0. That means that the voltage on the inductor is 0 as well at the moment. The part that confuses me is: why isn't the correct answer 0? How can a voltage change in a single moment? Furthermore I am...
  23. S

    Pressure Switch to Diaphragm Flow Switch

    I recently came across a Diaphragm flow switch whose operation many engineers are not familiar with. First. Supposedly in a normal pressure switch. The pressure will be a maximum when there's no flow, precisely because at zero flow there is no pressure drop anywhere in the system, so the...
  24. R

    Electrical How to wire an LED switch based on rated voltage and current

    Could someone please help. i need to connect a 12vdc motor which can draw 16 amps to a switch that has an led on it. the led is rated at 3v 20mA. The power supply i am using is rated to put out 12vdc at 30A I thought of the possibility of adding a resistor to the positive pole of the led. In...
  25. S

    Electrical Voltage readings in 14-3 Romex connected to combo switch

    In a house (USA) there is "combination switch" ( e.g. https://www.acehardware.com/departments/lighting-and-electrical/switches-outlets-and-plugs/switches/3235199?store=16359 ) containing 2 two-pole switches. [Edit: correction: 2 single pole switches]. The electrical diagram for the circuit...
  26. C

    What Are Suitable Alternatives for 4-Leg and 5-Leg Ronway Relay Switches?

    hi can anyone here recommend an alternative relay switch x2 one has 5 legs one has 4 im not able to find any the same :( and the ones I've looked at all have 5 legs the diffrece is Ronway RWG1-DC12V-HS and Ronway RWG1-DC12V-ZS Any help is appreciated :) hs and zs is the only diffrence i can see...
  27. kyphysics

    Which Circuit Breaker Switch to Turn?

    My home water heater is messed up. If I want to reset the circuit breaker for it, which should I turn? There are three: 1.) garage (where the heater is located) 2.) water heater/dryer 3.) heat pump
  28. C

    Circuits and the percent change of current when the switch is closed

    For an ideal battery (r = 0 Ω), closing the switch in (Figure 1)does not affect the brightness of bulb A. In practice, bulb A dims just a little when the switch closes. To see why, assume that the 1.50 V battery has an internal resistance r = 0.30 Ω and that the resistance of a glowing bulb is R...
  29. C

    Percent Change Of current when the switch is closed

    (.174A-.181A)/.181A=-3.86% but it says it wrong, and I did (.181A-.174A)/.174A =4.02% but this was wrong too. I've tried 3.87%,3.86%,-3.87%,-3.67%,4.02%, and -4.02% but all were wrong. I'm really not sure what to do here.
  30. M

    How to calculate the efficiency of a switch mode power supply?

    I know how to calculate the power output and input by analyzing the current in put and output with multimeters and using the formula P=VI. But P_out is obviously incomparably smaller than P_in so the efficiency would suck this way. Is there a better way to do this??
  31. D

    Physics Anxious about majoring in physics — considering a switch to engineering

    Hi all, I am a first year student at the University of Notre Dame, and I will be choosing classes for first semester second year in a week or so. I am currently a physics major, but am getting anxious as the time to “commit” approaches. I came in not knowing what I wanted to do as a career...
  32. dlgoff

    What does the standby symbol on power switches really mean?

    You see this symbol on power switches, but what does it really mean? From https://en.wikipedia.org/wiki/Power_symbol, But the switches that I've seen the symbol on doesn't cause a "sleep mode" but powers the device on and off. ... Grrr
  33. AbdullahS

    What do the symbols on an electrical switch mean?

    Hi All, I am just trying to understand a circuit but cannot figure out the meaning of the following symbol. Did not get very far from googling electrical symbols. The symbol is given below. I know it is a switch but what does "x" mean on one of the wires and what do the half sine and square...
  34. Aurimas

    How to design a slide switch mechanism to be waterproof -- ideas?

    I need to protect electronic parts in case from water. The thing is, I need to design slide switch on the cap of the housing. Maybe any ideas?
  35. C

    Schematics of a high pressure water switch

    Does anyone have internal schematics (or illustration) how this thing work inside? Like how water flow can activate the conduction to the two wires connected? https://www.amazon.com/dp/B01MU3KQCD/?tag=pfamazon01-20
  36. F

    I Where does gravity switch from stronger to weaker, if it does?

    I read everywhere that gravity is slightly stronger at the bottom of a mountain than at the top because the place is closer to the celestial body that causes the "attraction". What I don't understand is that, as you get closer to the center of the planet, there's less matter below you and...
  37. K

    Making a custom DIY light switch safe for home use

    Hi I’m making a custom lamp for a Christmas present and want to create a custom on off switch to go with it. The switch part is easy, just make a mechanism that breaks or completes a circuit, but I’m not sure what to do to insure it doesn’t electrocute the user, or burst into flames. If I...
  38. D

    Planning to measure voltage (back EMF) caused by opening a switch in series with an inductor

    i am planning to measure the back emf produced by inductor when you open a switch. i know it is very hard to predict the voltage. but is there any way to narrow the possibilities?
  39. K

    Any problem when a home power switch is staying between ON and OFF?

    I have a socket on the wall , because of the size of the adapter, the switch on the socket is always stayed between "ON" and "OFF" while it serves and works. From the electrical point of view, is it a complete circuit inside? is there any partial complete circuit which may be a problem?
  40. L

    Should I switch to Linux or Mac?

    Hi, For my next computer I either want a PC running OpenSUSE for coding and Ubuntu for gaming. I can code C++, Python, and Swift. I know that for Swift development you need a Mac computer. There's just no other way to code swift other than getting a Mac and XCode. But I know that Linux is pretty...
  41. M

    2-Resistor, 2-Capacitor Circuit with Switch

    I already did part a and got the correct answer of 4.8 microC. However, I am unsure how to approach part b, where the switch is closed and apparently the two capacitors end up with different charges. For part b, since there is a path between the two capacitors, I don't know if I am able to...
  42. H

    Timer based switch for a power capacitor

    To cover transformer loss at no load and maintain pf, we are needing 6kvar at day time and 9 kvar at evening. Is there any time based switch available, such that it can switch ON 3 kvar at evening, say 8:00pm and turn off automatically at 8:00AM morning
  43. german_cargo

    Replacing a remote with a switch -- voltage drop problems :(

    I have a linear actuator that raises and lowers my snow plow blade and the wireless remote stopped working. Rather than order a new one for $200, I decided to splice into the wiring and put a momentary switch in my truck. I didn't like the remote anyways. I grabbed some wire and wired up a...
  44. Z

    If a magnet could switch, could it attract and repel?

    Hello the first image with the letters going ABCD is picture #1 and then BACD is picture #2 for references. Tools: - Normal magnet. Nothing special about them. - And we will say they have some type of system where they do not move sideways. Only up and down and have a difference of 5 cm when...
  45. R

    Physics Should I switch to astrophysics?

    Like many of you, I have always enjoyed physics and math throughout high school. When applying to universities, I was quite unsure about my goals, so I applied to both engineering and science majors. I have always been deeply fascinated by astronomy, but I enjoyed environmental science as well...
  46. Z

    Earth's magnetic field -- How "suddenly" does it switch?

    I know, geologicaly speaking, that "suddenly" is a relative term. So when they say that Earths magnetic field suddenly switches, how long are we talking about. Days, hours, centuries?
  47. M

    Programs Switch majors from ME to material science?

    Hey, I’m kinda of in a crisis in my head here. I’m in the US to pursue my masters in mechanical engineering. After the introductory material science course, I believe I’ve got a greater interest towards materials than mechanical engineering. Would transferring to Material Science be a good...
  48. Krushnaraj Pandya

    Voltmeter readings across a closed/open switch in circuits

    Homework Statement The following figure shows a circuit containing a bulb, switch and battery. Four voltmeters are connected in it to measure potential difference. Which voltmeters give non-zero readings and which ones read terminal potential difference when the switch is 1) open and 2) closed...
  49. Lapse

    What is the Voltage on C1/C2 after the switch closes?

    Homework Statement Homework Equations Vf+(Vi-Vf)e-t/RC Tau = RC The Attempt at a Solution [/B] Normally, I would use the eq'n mentioned above to find Vr in an RC circuit. However, this second capacitor is throwing me off. Is there a new equation I should use? How do I think about this...