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.
This is a paradox that I have derived based on my understanding of relativity of simultaneity. Upon someone resolving it, I should be better able to understand the concept, which seems rather contradictory of the greater theory at this point in time.
If events are considered to be...
Alright, I came here looking for help as I haven't been able to figure out the answer.
in that picture the left is the bronze colour prong, following two are silver. There are numberings for each prong going 3-2-1 respectively from left(bronze, BUT the bronze pin has both a + and - sign...
Hello,
I am seeking advice on how to use an accelerometer as a switch on a CubeSat form factor. Incase you are unfamiliar, a cubesat is 1cm cube device designed to go into space. The problem is that the CubeSat must not have any electronics active during launch. I am seeking to use an...
Homework Statement
Why is it that the output is equal to V+ (when the switch is open) in diagram A, if there is no current flowing?
Why is it that A (1/0) is used by convention? I mean the lamp I got at home has a "0" for off and "1" for on, on the switch. This is confusing me...
A bill is being introduced in the U.S. Congress aimed at addressing Cyber threats. The bill, dubbed, "Protecting Cyber Space as a National Asset" or PCNAA, gives authority to the executive branch over the internet. A popular tag for this bill, is the "Internet Kill Switch", for the power it...
Hello all,
This is my first post so forgive me.
I am currently doing a internship for a wine company in Molina, Chile. They currently have a problem with the electricity; at 19:00 or so, the electricty company shut down the power, and they have to manually turn on the diesel generators for...
I'm working on a circuit to manipulate an existing signal for an automotive hydraulic hybrid product.
I need to pass on a 0.46 to 0.55V signal to the ECU during accelereration to keep the engine from revving and restore the original signal (0.55 to 5.5V) when the engine takes over.
This...
Hey all,
I'm a third/coming fourth year physics major and I'm starting to get a little apprehensive. Graduation is looming and I don't know if this degree is going to do very much for me. I'm afraid that when I graduate I will have no prospects for a job or career or no acceptances to grad...
Homework Statement
An LED is connected as shown (see attached)
When switch S is closed:
A. the p-n junction is reverse biased and free charge carriers are produced which may recombine to give quanta of radiation.
B. the p-n junction is forward biased and positive and negative charge...
Hi all,
I have been trying to get a MCU to send a +5v signal and in turn switch a N channel MOSFET with a VDS of +12v.
I used a P channel BJT, tied the gate to +12v through a resistor, the top to +12v straight, and the output to the gate of the MOSFET. Then by grounding the gate, the...
Ok, I know this may sound silly, but I enjoy programming and want to take it to whatever level I'm able to.
Effectively I want to be able to (through programming) connect to a device that has some sort of electrical "switch" and by "switch" I mean, "A device that can control the flow of...
Hey all,
I am trying to make a simple remote controlled switch (without any digital IC's) and was wondering if anyone knew of any schematics, etc.
Thanks,
John
Homework Statement
Provided in the picture below.
Homework Equations
The Attempt at a Solution
So what I've done so far is use KVL to obtain Vc(t) +Vr(t) + Vo(t) = 1/2Vin(t).
Could someone tell me if I started this problem correctly? Would I just take the derivative of the...
I had a question regarding a variation of the infamous Monty Hall problem. Assume four doors instead of the standard three. There is still one car and three goats, and of course the objective is to select the door with the highest probability that it is hiding a car.
You select a door. The...
Homework Statement
For the circuit shown below, the capacitors are initially uncharged. At t=0, the switch S is closed.
a) Determine the current in each resistor immediately after the switch is closed.
b) Determine the current in each resistor a very long time after the switch is closed...
"Normally On" switch
I'm making a computer component and I have constant power going to a npn transistor, I need a "normally on" switch to cut power to the npn transistor at different times. Anyone know a good website that discusses them.
Hi,
This is my first encouter with anything to do with RF design. I'm trying to design an RF PIN diode switch to meet certain specifications. I'm having considerable difficulty putting together a circuit schematic that will accomplish this.
My specs are:
Center frequency: 15GHz
Bandwidth...
Hello All,
For a hobby, my father, friend, and I are building a radio controlled tank. Without getting into to much ancillory info, the problem we are facing appears to be radio frequency interference.
Using a radio control transmitter, we are sending a signal to the receiver. That...
Homework Statement
i need to find the Vs(t) and Vc(t)
http://img32.imageshack.us/img32/9071/circuiten.jpg
The Attempt at a Solution
since there is a switch i used two cases to find the Vc
one with switch on and switch off
switch on...
I applied to graduate schools (for PhD programs) hoping to enter a place where I could be scientifically creative and collaborate with like-minded individuals.
I chose my current school because they offered me the best package, it had a good location, I was promised an RA position and I...
I'm a little confused about current flow/switches in circuits. Let's say two resistors are connected in parallel to a battery- if there is a switch between the two resistors on the negative terminal side, and the switch is opened, current won't flow through the second resistor, right? If current...
Hi,
I'm looking for a 6 pos, 2Amps, mechanical rotary switch that with every turn will short another contact to all of the other contacts that came before...
For example, if it's on position 3, legs 1, 2 and 3 will be shorthand all together.
Thanks.
Homework Statement
Homework Equations
Find v(t) for t < 0 and t > 0 in the circuit.
The Attempt at a Solution
I tried to find the i through the inductor for both t=0- and t=infinity, but I did not get the same result as the answer given in the txtbook which is 96e-4t V. According...
Hi experts,
is it possible to have a simple 2-directional switch using just 2 12v coil relays (having normally opened and closed contacts)? Is this equivalent to a h-bridge or must a h-bridge be used? The triggering is from a 555 to the relay coils.
I tested my circuit but it does not seem...
Homework Statement
So this is for a fourth year engineering project, I'm on the power subsystem of a lunar penetrator. I'm not in electrical engineering, I'm in aero (mech), so forgive me for my lack of specialized knowledge. I want a system in place where if the main power source fails (RTG)...
Hey. I am trying to build a circuit which would switch on/off another device. So far I have tried using an IR LED on the controller and with a phototransistor on the load device (which has it's own batteries), but I cannot figure out how to get it to work. I do not need complicated signals...
hi! everyone, um new to this forum and would like some help and few tips on designing a coding and decoding circuit to replace my car ignition switch with, for now all i know is the basics of logic circuit operations, still not enough to perform the function. can someone help plis!
I'm making an electromagnet for a contraption. As far as I know all the electromagnets demonstrated on the web are working permanently with supply of battery (Direct current). I need to know how i could make an electromagnet which works on an AC supply with a switch ? Please provide some...
Hi all. I am looking on how to make a single pole-double throw (SPDT) switch using phototransistors that can be activated by IR LEDs (not from a remote, i.e. in pulses, but as a single arrangement of a switch, cell, and IR LED).
Please keep it simple, I am only doing experiments. I don't...
Hey guys i have no idea how i would accomplish this, I am pretty sure i would made to make some sort of circuit but what i need it to be able to change where 4 wires go from a momentary switch like these.
an example would be to change which usb port a usb cable is connected to by the push of...
Homework Statement
I'm having a problem with the circuit in the attached diagram. I am looking for the charge on the plates of the capacitor a long time after the switch is closed.
Homework Equations
The Attempt at a Solution
I found the current leaving the battery is 0.962 A a...
I'm working on (building) a small induction generator setup. Its still well into the testing phase and i have a, what i think is anyways, rather complex question.
I know that the output characteristics (voltage and line frequency) of the generator at a given load is proportional to the...
As aforementioned, I have a L14F1 phototransistor. I am using this in a DC circuit.
A stupid question it is. Please take it seriously however. Read carefully; I repeat: how do I make a switch in a DC circuit using a L14F1 (3-pin) phototransistor?
And coming to why I don't use a 2-pin...
Dear all:
I am going to design a cantilever switch which is working with electrostatic (capacitive) force.
I want to design that. That is to find the dimension and material of that.
I was wondering if you could kindly suggest a reference for designing this.
Thank you very much.
Hello all... First, let me say that I am currently a graduate student in mathematics who would like to change graduate programs to something involving geology. I've always been fascinated with the internal Earth and how it behaves. To me, this seems like a big jump. My questions are the...
Hi all out there. I had recently salvaged an IR bulb from a TV remote (universal). The component I am in search for is an IR switch, that is, completes a circuit only when a signal from an IR LED is received. Could this also otherwise be made with common household stuff?
I know that I may get...
I am still a senior in high school and I am goin go to graduate next year and go to university next year.
I was in the career center today and the teacher asked how many students here are pursuing a career in Physics? And a few of us put our hands up.
The teacher said that it is a wise...
I am a CPA considering going back to school for B.S. in Engineering, or possibly doing Computer Science Masters/Ph.D. I would appreciate commentary anyone could provide on either of these fields. I am 35, btw ...
I would really like to do research and teach, so the ms/phd track is...
What current is flowing through the on/off switch?
The circuit below is powered by a 20-volt battery. What current is flowing through the on/off switch (When it is on, as shown)?
A. 0.23 amperes
B. 0.29 amperes
C. 0.32 amperes
D. 0.38 amperes
i tried myself i got a close answer...
I'm designing a circuit for a nixie clock and I seem to have two options for how I want to turn on the nixie.
http://img16.imageshack.us/img16/9181/circuit3l.th.jpg
The circuit on the left is what I originally prototyped and it seems to work fine; however, my friend has suggested that I try...
Im not sure if this should go here, but. . .
Im building a motion detector.
I have the breadboard hooked up the following way
using an op amp, a potentiometer, photocells, resistor and led.
http://img6.imageshack.us/i/breadboard.jpg/
So it seems to work fine, but I wanted to...
Dear Gurus,
I have a doubt about switches.
I have a proximity magnetic switch i used to switch on and off a circuit.
I wonder would there be arching or spikes or current surges when the switch is switched on and off repeatedly ? My circuit has resistors to limit the current. Will switching...
hello everyone ...I'm new here and I have so many questions need to be answered ! so I will be really really really thankful if you help :)
what should be the out put voltage waveform shape on the Oscilloscope "Vce" , when the 1Kohm resistor inserted and when it's not ...
the BJT as...
Hello,
I am having a little problem at the moment. I am working in a library, have been here for 5 hours now and I am losing focus, for example I read a paragraph 3 or 4 times and did not digest any of the information at all. So I think I need a break. The challenge is, if I get up I will...
The drawing shows two fully charged capacitors (C1 = 2.00\muF, q1 = 6.00\muC; C2 = 8.00\muF, q=12.0\muC). The switch is closed, and charge flows until equilibrium is reestablished (i.e., until both capacitors have the sam voltage across their plates). Find the resulting voltage across either...
Homework Statement
For the circuit shown in the figure below, C = 7.50 µF, script e = 80 V, and R = 400 Ω. After having been at contact a for a long time, the switch throw is rotated to contact b.
a.)What is the charge on the upper plate of the capacitor just as the switch throw is moved...
Doesn't a transistor switch need a mechanical switch? Otherwise, how does the transistor switch turn on and off? Does the switch have a "mind" of it's own?