Switch Definition and 565 Threads

Hello there! Now if I have a very very simple RL-circuit with a voltage source and we have a switch which is suddenly flipped in the off-position... does the SAME differential equation apply as if it's flipped ON? This I mean: \frac{\partial I }{\partial t}L + RI = U I do understand...

Hello PF inhabitants, I have just finished 5 years of university culminating in a Master's degree in biomedical science. I now work in a genetic diagnostics lab. Problem is I always had a deep 'urge' to do something quantitative and I always liked the seemingly inapplicable aspects of...

Hey guys, this is my first post on here. I'm a second-year physics major at a large public university in the U.S., and I am considering changing my major to mechanical engineering (with a physics minor. I faced this decision at the same time last year. If I were to switch I would have to stay...

C1=C2 Thanks

I have a BS in Mechanical Engineering and I've been out of school for almost 5 years. Several months back I started learning Java just for kicks, but I've reached a point where I'm pursuing more and more knowledge of CS concepts on my own, and the interested level is far exceeding that of...

Hi everyone , this is my first post here :) . I am an auto electrician , my hobby is photography. I am interested in high speed photography and have invented a new form of photography in a way . I call it 'superspeed photography' . It involves taking a picture of something that is triggered by...

Simple switch that "Remembers" state at power up? I've been trying to design a switch that, when a relay (spdt) is energized: -if a reed switch is closed, a 12v green light bulb drawing 2.5A stays lit until the relay is de-energized, regardless if the contacts of the reed switch open/close...

New to the site, looking for a little help. I'm trying to switch my motorcycle auxillary lights on and off using the flash to pass switch. I have a relay but only stays on when powered. Is there a switch I can put inline, or a switching relay that will work. Thank you

Hi, I'd like to do a small design project. When I sleep, I switch on my mosquito repellant for about 8 hours. Sometimes I forget switching it off too. Such long durations are little poisonous and generally not required. What I plan to do is to make a timer with a dial from 0 min to 60 min...

Hi everyone, my first post on here. I was hoping someone might have a few words of advice/suggestions. I'm a current sophomore currently pursuing biochemistry/molecular biology. My goal is to work in drug development of some sort, at a biotech company or so. Basically, I like to design and...

Hello everyone! I have a bit of an engineering puzzle. I've only a passing understanding of electrical engineering, so still trying to puzzle if out. Basically, imagine you have one black box A connected, via a single wire with a switch, to black box B. There is no returning wire. The...

I'm building a small project and would like some assistance from you folks. I have this motor 5rpm -12vdc and I'm using a Class 2 plug in transformer (input 12VDC 60Hz 23W - output 12VDC 1000mA) to power it up. I would like to add a IR LED/Phototransistor between the two to act as a on off...

Hello, I am currently in my Second year of Computer Engineering, but I often find myself not enjoying the electrical engineering courses that we have to take (Electromagnetics, Microelectronics, Circuits and Systems) but I immensely enjoy the programming courses and the Computer Engineering...

Homework Statement http://img689.imageshack.us/img689/6668/mycircuit.jpg Given a circuit that includes Operational Amplifiers, double-switch - S, for two situations, 1 and 2. Type of switch - DPDT - Double pole double throw. Two diodes and two lightbulbs, L1 and L2. Given: Voltage...

How hard is it to switch fields in science? For example, say you do your Ph.D. in an area of theoretical physics and are very successful, but cannot find further funding at some point (can't land a postdoc in your chosen field, no professorship offers, denied tenure, etc.). How difficult would...

Im not an elctrical engineer but I do need a source for the above mentioned switch. I would even be open to a simple schematic. Please Help.

[b]1. Homework Statement my teacher wants me to design a circuit to control the on or off of 4 BJTs in the circuit. Homework Equations The Attempt at a Solution so i tryed to control a BJT at once .. it workshttp://user.qzone.qq.com/259234914/infocenter#!app=4 but there were...

Can anyone tell me how to wire a momentary normally open switch to a battery operated device (4 AA batteries) like this one? http://www.scientificsonline.com/mini-plasma-ball.html Is it even possible? Any advice appreciated!

I think after completing my PhD I want to make a switch to medical physics. With my background (described below) this shouldn't be too great of a switch. (I wish I had realized this sooner, as in undergrad I was thinking biomedical engineering, but found myself far more interested in the...

I'm working on a project that uses a joystick to control a motor. The motor has an electric motor brake built in, and I want to be able to engage/disengage the brake with a button on my joystick. The motor runs on 24VDC, and the joystick runs on 5VDC. I currently have the button on the...

Hello!So recently I've been playing with 555 timers. And I am beginning to understand how powerful they can be.With that reset pin switching capabilities are endless. But that led me to thinking.How can I make that switch, which you have at your computer, that power on and off switch. The switch...

I have the following circuit wired up on a protoboard. The datasheet for the BSS138 MOSFET is here. I'm puzzled regarding what I'm seeing happen with this circuit - when I apply 3.3V at the gate resistor, the MOSFET turns on fully and I see 3mV at the output. This, of course, is expected...

Hello, I am designing a simple circuit and I need some guidance over snubber diode. When we open the switch, when we have a inductor in circuit, we will have that arc over switch which is something that we don't want. Using this snubber diode, we can avoid this. I feel that we will...

Hello Experts! Here is my simple clap switch schematic. First let me know is it correct or not? I have used 555 timer in monostable mode here this means LED will remain on for the particular period of time defined by R3 and C1 i.e. T=1.1(R1)(C1). Let I use red LED here. So I think 1.7V is...

Hello, I'm considering using a logic-level MOSFET as a switch in a design. The drain of the MOSFET will be connected to an IC. The IC works at 3.3V and the maximum voltage at which it's guaranteed to read a low is just 0.8V. Now, I think every MOSFET will able to satisfy this but I'm just...

Clamp switch using 555 timer in monostable mode(Working of components) Hello experts! Here is my circuits in the attachments.(Monostable mode of 555) All values of components shown here have been chosen by myself and all are arbitrary. I want to ask some question about this circuits. i.e...

Hi everyone. My problem is for an assignment in a network analysis course. I attached the homework page as a pdf. Homework Statement My problem involves an R-L circuit with a switch. There is a 100 V source, and switch that is initially closed, followed by a .25 H inductor and a 200 Ohm...

Hello Please my apologies for mistakes as I am a new member, and I would like to ask a how to question,I am trying to make a system up that I can use on my racing cars ( classic hence no onboard computer ) What I want to do is to have a 12 volt pulse(from 12 volts to o volts) that I can use on...

Homework Statement i have the divergence in the (x,y,z) Cartesian as \frac{dA_x}{dx}+\frac{dA_y}{dy}+\frac{dA_z}{dz} and the assignment is to transfer it to cylindrical system (r,{\phi},z), by any way i choose. Homework Equations tried with the chain rule, but i am doing...

i recently had a lab where i needed to build a circuit with a debounced switch in it. now i have to explain how the debounced switch works but I'm having trouble articulating the different operations that occur. the circuit consisted of two wires each with a resistor of the same type and...

So I've been contemplating switching my ME major to physics for months now, and I'm still having trouble deciding. I really love physics, but I don't want to regret switching. I've read in some sources that Physics majors are extremely employable, while some claim that it's a worthless major...

I have looked everywhere for help with this, and I can't find any. I am trying to construct a mechanism that will rapidly switch a DC circuit on and off, anywhere from 10 to 100+ times a second. Ideally this switch should consume as little power as possible, and should be powered by a 6 volt...

In the circuit below, the switch reaches a steady state while in position 1 then at t = 0 gets thrown to position 2. I am supposed to find the voltage (s-domain) across the capacitor under these conditions using thev. theorem I just want to make sure I am approaching the problem with the...

i am in no way a engineer so i need help i just bought (MICRO SWITCH, PIN PLUNGER, SPDT 16A 250V; Microswitch Type:Standard; Actuator Style:Pin Plunger; Operating Force Max:100gf; Contact Voltage AC Nom:250V; Contact Current Max:16A; Switch Terminals:Quick Connect; Circuitry:SPDT) and it...

Hello knowledgeable ones! I need your help to make my life easier; Background. I need to turn on fans every cold night during winter in a grain storage shed to keep the grain from heating/rotting! This involves treking to the shed in the cold after midnight (cheap electricity) and...

I'm a second year Aerospace Engineering student and I'm wondering if this is the best career path for me to take. Since a young kid I've always been fascinated by the universe and everything related to it. I want a career that will let me progress our knowledge of space forward whether it's via...

Good evening to all I wonder if anyone can help please I have 8 switches b1,b2,b3,b4,b5,b6,b7,b8 I am trying to work out how many permutations I would have if I pressed any 4 of the 8 switches ie if I pressed b1,b3,b,7,b8 to make a circuit or it could be b3,b5,b6,b7 doing it by long hand I...

I have a push-button switch rated at 3 amps @ 125vAC which I want to use in a 12v DC application (my motorcycle). ((on ground line under continuous use {headlight})) Does the AC rating translate as 3 amp for 125v AC hence 375 watts 375 watts for 60v AC hence 6.25 amps or 375...

I'm trying to learn about MOSFETs in order to use them as a switch. (note: this is not a homework/school question). On my breadboard, I have the following circuit hooked up: I vary the gate voltage using a potentiometer. Here is what confuses me: according to wikipedia, the MOSFET is in...

I am a wheelchair user trying to find a way to trigger certain functions on my chair from a PC. Basically what I have right now is a switch like this: http://www.enablemart.com/Catalog/Sensitive-Switches/Micro-Light-Switch My goal is to emulate that switch with a software program, which of...

Homework Statement For the attached circuit (which I've drawn rather poorly in GIMP), I need to figure out the charge on each capacitor when the switch has (a) been closed for a long time and (b) been open for a long time. Homework Equations Loop and Junction rules, \DeltaV=IR...

Is there a way to minimize the temperature dependence of VBE. I am trying to design a BJT switch, that will turn on at a particular voltage(43v). ckt attached. The base sees 0.65v when Vcc is 43v or more (resistor divider bias). This turns on the BJT. It should be off when Vcc is 42V or...

Hello, on my robot I essentially have two sources of power. #1. The first is my 9-volt battery to the BS2. (+ pin 24, - pin 23) #2. my second is a power source for the motors. it uses four C batteries not directly connected to the stamp but with it's own system of circuitry. check...

I am entering into graduate school next year and strongly considering going from a bachelor's in physics to a Master's EE program. One of my main reasons for doing so is that I am interested in more tangible hands on work as opposed to more computer coding based tasks and intense theory. Does...

This is a question that was on my test Homework Statement http://img269.imageshack.us/img269/5125/circuitthingy.jpg In the circuit in the drawing switch S is open. Both resistors are idential, both having resistance R each. Given the source is E, and R = r (the resistance of...

Hi I am looking for off the shelf switch which can handle both 220v Ac and Battery(dc). output of the switch should be 12vdc, when powered by AC it should automatically cut the DC and start Charging the battery and rectify AC to DC. Please help.its really imp for my project.

I am looking for a switch or relay to switch high voltages on and off based on a digital input signal. Below are the characteristics of the device I would like to find. Switching frequency: 100 Hz to 100 KHz Input (control) signal: square waves, 3 to 12 volts amplitude, 100 Hz to 100 KHz...

In a BJT PNP switch, why does the base voltage need to go to zero to turn it on. If Vee is 5V, the base has to be 5-0.7v to make the BE fwd biased.

So, a professor in class a about a year ago mentioned that opening a switch in a circuit that an inductor is providing power to would cause a breakdown in the air and a spark would jump across it because the current can't change instantaneously to zero in an inductor. Something just made me...

Hello, I would like to know if there is a part I can buy that will alternate my dc power circuit on/off at short intervals automatically All help much appreciated, Cheers, Nick