Switch Definition and 565 Threads

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. Topher925

    How to eliminate arcing in a switch?

    I'm working on a project where I'm connecting a big 36V battery to some electronics which contain capacitors on the power input. Of course when I connect the two I get some major arcing which likes to weld and stick connectors together. Does anyone know of a simple or easy way around this? The...
  2. Y

    IT and I want to switch to Astrophysics

    Hello everyone, I hope I'm writing this in the right forum. I am so desperate for guidance == Long story short == I have a BSc in Information Technology and I want to get into astronomy and astrophysics for graduate school. how can I make this shift in fields? do I have to go...
  3. rhody

    TED Video: Ed Boyden: A light switch for neurons

    Interesting http://www.ted.com/talks/ed_boyden.html?utm_source=newsletter_weekly_2011-05-17&utm_campaign=newsletter_weekly&utm_medium=email", I thought I would pass it on. Ed Boyden shows how, by inserting genes for light-sensitive proteins into brain cells, he can selectively activate or...
  4. C

    Create a Wireless AV Switch for Simple RCA Audio Input Toggling

    I'm trying to figure out the easiest way to make a simple switch that toggles between two different RCA audio inputs. I can do it easily with a physical switch but how can I do it remotely. Either from a remote or from my cell phone (so either IR, Bluetooth, or WiFi). I'd prefer using my...
  5. H

    What Is the Name of the Switch That Turns Off a Water Pump Due to Low Pressure?

    What do you call a switch that switches off an electric powered water pump if the pressure drops to low? An example would be if the filter gets clogged up and the pump doesn't get enough water. I see a lot of "water pump pressure switch 40/60 psi" but that is not it. I don't know what...
  6. T

    Calculating Charge and Voltage in an RC Circuit with a Closed Switch

    Homework Statement Switch S has been closed for a long time, and the electric circuit shown in the figure below carries a constant current. Take C1 = 3.00 µF, C2 = 6.00 µF, R1 = 4.00 k, and R2 = 7.00 k. The power delivered to R2 is 2.60 W. Homework Equations (a) Find the charge on...
  7. B

    Designing a Computer Controlled Switch: Components and Steps

    Hello, I am interested in making a computer controlled switch. Can anyone give me a simple overview what components will I need and how should that work. I am aiming for making/designing my own circuit. I just need schematics and steps. Thanks
  8. D

    Why do switches spark when opening a connection to a load?

    What causes a switch's contact to spark when you use it to open a connection to a load? I can understand why the contact sparks when opening an inductive load (inductive reactance), but what if the load is purely resistive?
  9. R

    A question re solid state switch

    I am less than a novice regarding electronic issues and understanding circuits , and need help in terms of seeking a component. I am looking for a solid state component---?? ic--- that would act as a SPST switch. This switching device would be inserted into a simple dc circuit--( approx 10-15...
  10. J

    Build Automatic Water Switch with Engineering Knowledge

    I am wanting to make something that allows me to open a valve to turn water on or off. I am wanting to figure out a way to make my system somehow that would use maybe an alarm clock or some sort of digital timer to send a signal to a receiver that then would open/close a valve. I guess it's...
  11. F

    What is Switch Bounce? | Project Study Info

    Ive been working on a new project for my studies but can't seem to get any info on 'switch bounce'
  12. B

    High Current Switch Solution for Hobbiest

    Hobbiest here trying to make a rotary switching system to switch between a 1000w DC power supply and an external DC supply of the same input plus an all turned off position. The first power supply is running at 12 vDC and the 2nd input could be anything from 8-36 vDC. I can find rotary switches...
  13. J

    Change out switch on controller

    Greetings everyone, I'm trying to figure out how I can take an old Rock Band kick pedal and make it activate a button in a controller. I've uploaded pictures to help explain. Simply put, I want to make the kick pedal which already has some sort of pressure switch in it to activate the button...
  14. I

    Designing a PWM Switch with RC Circuit and Schmitt Trigger for 50 Hz Frequency

    i am trying to design a switch that will output an active high if the width of the received PWM signal is greater then 1500 uS. if it is shorter then this time then it should output an active low. The frequency of this signal is 50 Hz. I designed a RC circuit with a cutoff frequency of 50...
  15. A

    How Can I Create an Adjustable Optical Switch Circuit for an Inductive Load?

    i'm trying to make an optical switch circuit. i'm no expert on electronics, so i was hoping you people could give me a helping hand:) in advance, thank you very much:) the purpose of the circuit is to switch an inductive load such as a relay. when the light is blocked i need the relay to...
  16. Jonnyb42

    Physics Should I Switch Degrees to Pursue Nanotech Research?

    Hello, I am having a lot of trouble deciding if I should switch to a physics degree or not. I am currently in Electrical Engineering, about to finish my second semester, (first year.) My thoughts on switching to physics having nothing to do with a dislike towards engineering, I very much like...
  17. C

    Programs Should I switch to a math major?

    Hi all. First, I'm pretty new here, so I apologize for any faux pauxs I might make. Anyway, I'm a freshman in college right now, and my current major is chemistry. I don't really know if I want to stay in chemistry though, because I only ever want to work on my math class and german class...
  18. D

    Automatic Transfer Switch Problem

    Hello, I have an ONAN OTUDD100-4/1201C (Serial j810595543) automatic transfer swicth for a 30 KW 120/240 V 3PH Generator. The control panel is also 3PH. Nonetheless, the power company electric supply is 120/240V 1 PH 3 Wires. My issue is: 1. When we connect the above-mentioned current...
  19. A

    Potential difference in circuit with battery, resistors, switch, capacitor

    Homework Statement Consider the circuit shown in the Figure, where R1 = 29 and R2 = 4.8 . http://www.webassign.net/walker/21-44alt.gif (a) Is the current flowing through the battery immediately after the switch is closed greater than, less than, or the same as the current flowing...
  20. P

    Physics Can I Switch to Theoretical Physics? A PhD Student's Confusion

    Hi. I'm currently a 4th year phd student in astrophysics, studying compact stars. I'm from China and am now an exchange student in US. What I'm asking is: if I really have more interest in theoretical physics, do I still have a chance of entering the field? I'm now in a very confusing stage...
  21. B

    Non-Touch Switch: Finding a Component Solution

    Could anybody point me towards a component that could serve the purpose of a non touch switch. To explain it better, one that would trigger when an object or hand were to be placed within say a few centimeters away from it - capacitive switches I've seen all work by touch. Id like an array of...
  22. F

    Buck Converter High-Side Switch

    As a hobbyist I have had an interest in SMPS power supplies for quite some time, but have never gone past casual study of them. I understand the theory, but have difficulty with the actual implementation of things like a high-side switch mechanism for a P-Channel Mosfet. My goal is to...
  23. F

    I am tired of using Maple, I am going to switch over to Mathematica

    Homework Statement That's right, Maple is the dumbest program in existence. Everything I try to erase a line by hitting delete or backspace, it won't disappear. When I want to use an function, I have to load a package ex. "Student Linear Algebra" to use a certain command. Sometimes the...
  24. S

    Switch vs. If: Comparing Conditional Statements

    What is the difference between switch statement and if statement?
  25. B

    Switch to a large company for future opportunities?

    I am early in my career working for a small niche company right now, doing a lot of mechanical design. It seems like great experience to me; I am learning a lot about machine parts, manufacturing processes, and drawings. However, I might have an opportunity to move into a large, well-connected...
  26. R

    All-in-one product to remotely switch AC outlet?

    Similarly to air switches in hot tubs, I am looking for a UL Certified product that includes a SPDT switch, relay and transformer to plug into a standard 110V 15A outlet. The relay would be energized by the low voltage from the transformer and activated by the SPDT switch which would then switch...
  27. P

    How to Design a Remote-Controlled AC Power Meter with 5V DC Supply?

    Hi, I have forgo my previous idea of Tesla coil as my final year project and now moved on in doing an AC power meter monitoring, which monitors the kWh, voltage, current consumption of a device and remotely controlled switch to turn off/on the device.This power meter should be implemented like a...
  28. A

    Inductive Proximity Switch Build Help

    I am trying to put together an inductive proximity detector for Rail Wheel detection. Currently we use an oscillator connected to a coil. We then count pulses on the oscillator and measure a detect when coil saturation changes the pulse. There are similar industries that use NAMUR...
  29. J

    Some ideas to switch to that wireless receiver

    Hi Please don't give me another warning for posting in a wrong forum. Seriously, in my view this belong here in "General Discussion" forum. Where I'm placed these days here we have electricity blackouts several times a day, sometimes for as long as 3 hours at one time. My laptop could run...
  30. T

    Relay for Infrared controlled switch

    hi,, i m building this IR receiver circuit, to work as a switch for electrical appliances such as a lamp,, so when i send an IR beam to the circuit, the lamp should turn ON and stay ON even the beam is no longer present, but it should turn OFF when i send IR beam again. Which relay...
  31. C

    Maximizing MOSFET Switching Speed with High Voltage Pulse Techniques

    ok looking at datasheets for mostfet there is source/drain rise and fall time. does this only depend on the voltage rise fall time of the gate? so if you apply a voltage to the gate it will take a wile until the voltage of the actual gate reaches that of the applied voltage because of...
  32. J

    Frequency Switch: Ideas & Advice

    I'm trying to build a switch that is closed only when the input signal is roughly the same signal over some time. So when ever the frequency of the input changes by a significant amount the switch opens, and when the input frequency is roughly constant the switch is closed. I'm building this in...
  33. D

    Math Should I Switch from Chemical Engineering to Mathematics?

    I'm studying the second year of a chemical engineering degree. I have always loved mathematics, and I am pretty good at them, and since the beginning I am not satisfied with the engineering approach to mathematics, I would like to learn some more complicated math, but I'm not quite sure if I...
  34. J

    Looking for a push button breadboard switch

    Can anyone recommend a push button switch that fits into a breadboard from mouser.com? I just want a push button switch that I can use to switch between Vcc and ground to use as the clock for a counter, but there are so many switches on mouser and I'm not sure which one to get. Can anyone help?
  35. M

    Timer Switch Questions: Answers & Solutions

    I am trying to figure a way to hook up a timer to my pellet stove. The control board of the stove has an "on" button and a separate "off" button. The on button is a push button switch. My question is: is there a programmable timer that closes a circuit for a second and releases the switch like...
  36. J

    Need help else, else if statments switch case

    need help else, else if statements... switch case.. need help on the bottom where tryin to define bonusContribution // Marcus Molineaux csit 802 assignment 3 t th 645 #include <iostream> #include <string> #include <iomanip> using namespace std; int main() { int tiksold; double...
  37. A

    Engineering Basic RC Circuit but with parallel switch?

    Homework Statement I want to find ix in the circuit below when the switch opens at t=0 after having been closed for a long time.Homework Equations v(t) = v(infinity) + (v(0)-v(infinity))e-t/RC i(t) = C dv(t)/dt ix = isource - i(t) v(t) = voltage across capacitor i(t) = current through...
  38. Z

    Considering a switch to theoretical physics

    Considering a "switch" to theoretical physics I'm a math major with 5 semesters left as an undergraduate. My math "profile" is very strong: lots of graduate classes (commutative algebra and algebraic geometry, homological algebra, higher homotopy theory and homology theory, representation...
  39. V

    Finding i(t) Across R3 & R2 After Switch Closure at t=0

    Homework Statement The switch in the circuit has been closed for a long time before opening at t = 0 a. Find i(t) across R3 for t>0. b. Find i(t) across R2 for t>0. I have attached the circuit. Homework Equations The Attempt at a Solution The only thing I know for this problem...
  40. N

    Thermal Switch Design Project fast

    Homework Statement There are three vertical metal strips (Steel, Aluminum, Steel) between two horizontal rigid bodies alphaa = 12.5 E-6 /degF -- coefficient of thermal expansion alphas = 6.6 E-6 /degF Ea = 10 E6 psi -- Young's Modulus Es = 30 E6 psi The original dimensions of the...
  41. S

    How Can I Use an Analog Switch to Obtain Specific Waveforms in My Circuit?

    Hi all, I have a problem with an analog switch DG201 in my analog design circuit. The circuit has 2 input at the early stage, v(t) and i(t). v(t) will be changed into TTL square wave and go through a sample and hold circuit. And the i(t) will be go through the sample and hold circuit as well...
  42. M

    Buzzer for a normally closed switch

    I'm sure there is an easy solution to my problem, but I very little electronics background and don't yet have a breadboard to even experiment on. In fact, it was only two days ago that I learned a 555 doesn't need to (or can) be programmed by a computer to use. I want to make a buzzer that...
  43. K

    Feel really stupid. Need help. Thermal switch design problem.

    Homework Statement There are two rigid plates on the ends. In between them are two steel plates and one aluminum plate. The aluminum one is in the center. When the temperature increases enough the aluminum will buckle and touch one of the steel plates to close the circuit. alpha(alum)...
  44. E

    How can I add an end switch to carraige system

    I have a carraige being operated by a transmission drive on a 120v 3ph 2hp motor. I am using a magnetic contactor, followed by a reversing drum switch (a later addition when they didn't want to push the cart back after each run). Now they want to add a switch down by the end of the tracks to...
  45. J

    How to make a remote control on / off switch

    Hi all, I would like to make a simple remote control on / off switch. It is for a string of LV leds. 12 V and 0.24 amp running from a battery supply. I would simply like remote switch instead of a toggle so no one else can fiddle with it. Can anyone help me, I have been scouring the...
  46. S

    Standard/wifi light switch schematic

    standard/wifi "light switch" schematic Electrical engineers, I would like to learn more about circuits, wireless applications, and their integration with computer software. So I've come up with an idea to bounce off of you. I would like to be able to create (and eventually install) a wireless...
  47. S

    Dg201cj cmos quad spst analog switch

    Hi..anyone here can explain to me what is the function of this device DG201 CMOS QUAD SPST ANALOG SWITCH? I had search using google or yahoo search machine but still can't find any site explaining this device. So if you know what is it please tell me or paste the link for me here. I dun want the...
  48. M

    Courses Stay on Theoretical Physics course or switch to Maths & Physics?

    Hey guys, I know this is predominately an american centred forum but I was wondering if anyone could give me some advice. I've completed the first year of a Theoretical Physics 4 year course at Durham (in the UK). However with the modules that I chose I do still have the option to swap over to...
  49. C

    Solving for y: Why/How do y and e^x switch places?

    Homework Statement Doing a DE and need to solve for y, just wondering about this particular case. Homework Equations ln ((2y-1)/(y-1)) = x for y The Attempt at a Solution Wolfram says the result is...
  50. L

    Connecting Fan 2 Wiring to Auto/On/Off Switch

    What I'm tring to do is connect FAN 2 Wiring (673 DKBLU 2nd picture top diagram) to The Auto pole of the AUTO/ON/OFF switch so I can manually activate the FAN if needed. I'm a little confused since in the 2nd pic, I don't see a Negative side to the coil on the relay. Can/will this work?
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