Switch Definition and 555 Threads

Homework Statement http://imageshack.us/a/img831/8798/homeworkprobsg31.jpg Assuming that the switch has been in position #1 for a long time; at t = 0 the switch is moved to position #2. Calculate the current i(t) for t>0.Homework Equations Q = CV V = IR V(t) = -V0*e-t/RC (V0 is the...

Hey all, I bought a cathode light kit for my PC case a couple days ago and decided I wanted to mod it so that I could have a switch on the front of my pc to easily turn it on and off. Today I spliced the wire and threw a switch on and soldered it up. I've tested the switch and it works...

Here's my circuit The question at hand is what happens when the trigger switch is closed during the timing cycle (after being closed once already to initiate said cycle) here's the waveform I'm getting, but I'm not sure what to make of it. could someone please help me understand...

Greetings, I am looking for equivalent of relay or optocoupler but in nanowatts range if there is any. I looked into a MOSFET however gate switch cannot be isolated and there is Id drop when conducting. Relay is cool because there is no current drop or voltage drop when switch is on. Timing...

http://imgur.com/PQ4XCEo 2.V=IR 3. I know the capacitor has a voltage of 5.5 because it is charged to the supply voltage, I don't understand what happens to current when the switch is opened.

hello friends, I am looking for a 6 Pin DPDT switch to which DC voltage will be given as input My input DC voltage range is from 80V ~ 150V and dc current is less than 5A. When i searched the internet i could only find DPDT switches with following ratings 125VAC/3A and 250V/2A or...

How does a transistor work as a switch and amplifier?? i know a transistor is a device that controls the flow of current but how does it act as a switch and an amplifier? i tried reading about it on so many places but i just can't seem to get it :confused: ...the diagrams just don't make sense...

Hey gang, I am trying to figure out a solution to a small problem i have.. and it is probably really simple, especially to you guys. I want to be able to power on a series of monitors and then a PC, with a small delay, by turning the main power switch on. To give a better...

I'm in the process of repairing a lamp that I found with a broken switch. I know the lamp mechanism is functioning because I've bypassed the switch and plugged it in and it works fine. I needed to buy a new switch and they all have a current rating. I'm using 1 60 W bulb with a standard North...

Hi everyone, Right now I'm pursuing a BS in molecular biology and I decided I'd like to switch to a Bs Ed. in biology and teach high school biology. I'm 49 credits in so far just looking for some advice, part of me wants to finish the Bs degree and then get certified K-12 at the graduate...

Hello, I figure if anyone on the internet would know where to find a good solution to my issue, it would be you guys. For a tiny bit of background, I am building a Virtual Pinball Cabinet. I want to control two inputs with a single switch.. To be exact, I want to emulate the setup that...

I'm trying to figure out a bit of a http://www.ck-components.com/tpc/navigation,10475,en.html. Data sheet is in the Literature box marked "Download TPC catalog pages". The electrical sketch on page two is what's confusing me. How would I read this switch to figure out what its state is? This...

How do you design a BJT switch to ensure it is (Vce) saturated.

If this post looks too long for you to read, please go to the end, read the summary paragraph and respond to that. I'm going to summarize my history as concisely as I can without leaving out any important info. So I got a BS in Neuroscience (3.8 GPA), and throughout undergrad, I knew I...

Im new here and I am currently working on a small IR encoder project. I have the encoder working great but now I need to use the 5vdc signal that comes from the encoder and make it 24vdc. I am currently trying to use a bipolar transistor but its not working. The basic diagram that I am going off...

Hello, I wish to switch ON and OFF a high-voltage (that generates a high electric field) using a ultra-fast laser as a trigger. Basically I have a flow of charged particles that I want to quickly deflect using an E-field. The timing must be correct and controlled by a LASER. Does anyone...

Hello, I have a set of switches that would look good on my project however they are all tactile SPST. Is there anyway (without the use of an IC) to turn these momentary switches into a SPDT and/or a latching SPST. I want to switch the circuit on and off with a green and red led changing...

The title, basically. If we're at a temperature below the critical temperature (let's just say for a Type 1 superconductor) and an applied magnetic field less than the critical magnetic field, it will be in the superconducting state. But if we increase the field beyond the critical point, it...

Homework Statement See figure attached. Homework Equations The Attempt at a Solution See figure attached for attempt at the solution. Can anyone verify whether or not my workings are correct?

For a rc car model, is there any way to reverse the current like a speed controller would but without one to be able to make the car reverse? I have been contemplating the option of three way switch but I'm not sure if it'll work. Any other helpful ideas?

NO Reed switch in magnetic field. What I'm wondering is, a normaly open switch is closed in the presents of a changing magnetic field. Would the switch be closed when the field is present but not changing? I'd rather use a Hall sensor but know very little in how I would hook that up to my reed...

Hi I am trying to make an LED 3.5V 0.02A run in a circuit that will turn it off when visible light comes on. I have a cadmium sulfide photocell I took out of a night light. The power input is 12V 250mA. I understand I need to use a transistor as a switch for the LED and I know how to calculate...

Homework Statement Ok so I have been given a diagram which if it worked should be attached. I am having a fair bit of trouble understanding it. Now I am aware that there is both electrical and conventional currents but I am confused as to whether this is electrical or conventional. I have been...

I post to this forum, because I want to analyze this phenomenon with the aid of those who may understand the various nuances of scientific theory, by which such a thing could occur. I do not feel that posting to a forum dedicated to audio/video would yield quality results. This matter...

Let's say I get my undergrad degree in EE, but then decide to go to a different major for graduate school (i.e. PhD). Which of the following would it be feasible (or even possible) for me to switch to: - Economics - Computer science (theoretical) - Computer science (applied) - Applied and...

Homework Statement I am given a problem for my electronics class that asks to design a transistor switch that will switch a 10-Ohm load powered from a +5V supply. The transistor beta is about 50. It also asks which current is needed to turn the transistor fully on (saturate it so that the...

I have a new problem where I have 2 formulas, and I need to tell my program that at certain intervals/parameters/bounds it needs to do one of the formulas and at other intervals it needs to do another one. To be more descriptive When ever my time=0 to time=(T/2) it should do formula 1, and...

Homework Statement EDIT: The chain is connected to a battery, thus the current in this chain is direct. When the electric chain's switch (J) is on, resistance [SIZE="4"]R[SIZE="2"]ab (from dots A to B) is equal to 80 Ohms. What is the electric chain's resistance when the switch (J) is off...

Homework Statement You're given an electronic switch which requires 5V at 1mA in order to close; it is open with no voltage present at its input. If the only microphone available produces a peak voltage of 250mV, design a circuit which will energize the switch when someone speaks into the...

Am doing a project that has to use a transistor, as a switch, actually switching a 12V relay switch, that is actually responsible for switching another circuit, but as a result the relay doesn't switch ON, but makes noise continuously, in this clearly certain that the voltage across the relay is...

I've watched this youtube video : , and understood it only a little so i came here for help. How does that three terminal rocker switch work. It says that the terminals are for power, ground and acc.(Is acc accessory which means load??) If for example, i want the switch to control a simple...

We may solve a function or check a theorem but sometimes the mathematics is easier when we switch from different coordinate systems. What can we look for that tells us changing is a good idea?

I'm reading about selection rules, and the book is talking about how if you have a parity switching operator in between two wave vectors of opposite (definite) parity, the result is 0. For example, we have \left\langle2,0,0 \right|\hat{X}\left|2,0,0\right\rangle = 0 because...

I have a battery operated digital timer circuit board that will control a small motor, via a control board. The timer runs on 3.6vdc (batteries). The timers Output Control Signal is 3.6vdc when on, and 0Vdc when off. The timer is replacing an old analogue timer. The old timer had normally...

I need to find a switch that can detect whether it should go from 9v source or 5v Source. I am making a tool that has a battery power of 9v and it can also get powered from a USB device, which is 5V. If the customer need to connect the tool to a computer while its running from the battery...

Hi, Now I work as a QA in an IT company and I want to switch to PM in future. What steps should be taken ? Currently I am into CAPM and reading some forums. 1.What is the path to reach my destination project coordinator -> Junior PM / Assistant PM-> PM ? will this work? 2. How long it...

electric circuit -- Why is the switch needed in this capacitor circuit? Hi, I have two questions with respect to the picture in the attachment.: 1) I have read, that the capacitor become charged, when the switch is closed. All right, but why the capacitor doesn't became charged before...

I have a motor that is running off bridge-rectified mains voltage. There are no filtering capacitors across the rectifier output. When figuring the ratings needed for any switches in series with the motor, would I use the AC or DC ratings of the switch? My understanding is the biggest...

Dear PF, How are you? I am fine. So we are going to be out of the house for a month and I figure it would be a terrible waste of electricity if we had someone house sit for us. Does anyone know if anyone makes some sort of device that will turn on and off a light in our house for certain...

I'm need to simulate a circuit with a FST3126 4x bus switch in Multisim. I was planning on using the component wizard to make an FST3126 as it's not one of there components, but I'm not sure how it works. Looking at the data sheet logic diagram I though the component acted like 4 switched...

I have heard from not very educated 'technicians' who installed my air conditioner, that I must first switch off the compressor of the AC by switching it to fan mode, and after some time, switch it off, to avoid some kind of collection of cold air inside it. I kind of followed it for the time...

For this exercise: http://img651.imageshack.us/img651/6953/maingyx.jpg I found six http://img72.imageshack.us/img72/3215/gimel.jpg http://img842.imageshack.us/img842/3260/gimelb.jpg That's it, right?

Hi, I am trying to solve a problem, where i need to find the switching time of a mechanical switch. A voltage of V is applied to an acutation pad, and the movable beam is assumed to have a spring constant of K. I have attached the photo for better clarity. Please help me out...

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...