Troubleshooting — 319 discussions

Please tell me which one is wrong! When I put a mass M on one end of a spring!

On occasion my keyboard locks up. IBM thinkpad, Windows 7. It occurs when I am typing a message in a forum like now. Fortunately my mouse still works, so I can save the (incomplete) message and then restart the computer, freeing the keyboard. Any ideas why it is happening and is there a...

I know this is so vague as to be unanswerable - at least no answer better than I might come up with through a bit of experimentation - but it's late and I'm lazy. After having my new Smart TV with soundbar for several months now, it has spontaneously started doing something different. The new...

Hi all, 1500W 12Vdc to 110Vac modified sine inverter. Two output MOSFETs shorted and took some of the driver components with them. I removed all the MOSFETs, and fed in some power carefully - once the voltage rose to 12V, I could see the large output caps were being charged to over 200V, and...

I've been following the derivations in the following video up until that point. I don't quite understand why does it imply that μ*ε=1/c^2. Thanks.

I am working on a switch mode psu in step down configuration with the key components being: LM2592 (adj) http://www.ti.com/lit/ds/symlink/lm2592hv.pdf 530-PC-24-1000 http://www.mouser.com/ds/2/643/PC-594199.pdf GSIB-25 http://www.vishay.com/docs/88646/gsib25xx.pdf Using a slightly modified...

I know that its well above average. So I got A= 15-B, C=B+9 and D=B+21, but I think I made a mistake somewhere

I am stuck on this chemistry problem using Mastering Chemistry to do my homework. This is the problem. When I enter the answers it keeps saying is that "One or more of the units you entered is not recognized." **My Answers**For part A my answer was 426 g P2O5 and for part B 369 g...

Hey guys, hello. There is a system belongs in internet called LON-CAPA, and my teacher told that homeworks are done via that system. So I logged in, the questions are not that difficult to solve. But system doesn't accept some of my answers which I'm so sure that being true. So I'm going to...

I have a DC powered pump, that has suddenly stopped working. During troubleshooting I came up with the following results, that I just cannot reconcile: Input wires, not connected to pump: 12v Input wires connected to pump: 0v Sounds like a short in the pump right? However, connecting the...

I have an overhead crane and we are having some issues with the gearboxes that drive the bridge. The total crane weight is 44250lbs and has a 4 ton capacity. The wheels are 13.5 inches in diameter and have a wheel load of 16500lbs. The gearbox is driven by a 2HP electric motor at 1750rpm...

I used a table generator site http://www.tablesgenerator.com/ to create this latex code, but it doesn't work in a thread when I paste it in between dollar dollar delimiters. Help please. $$ \begin{table}[] \centering \caption{My caption} \label{my-label} \begin{tabular}{ll} 1 & TW base...

So I have a vintage analog TEKTRONIX 2465 Oscilloscope that I bought used on eBay for a bargain of $300 last year. When I got it worked okayyyyy except when there was no input the CRT would display Channel 1 and 2 lines slanted and pressing the BEAM FIND button didn't help(nor adjusting the...

I am trying to understand N-spherical cap area formula (surface area of blue part), but it seems to give wrong answers. for 1 dimensional cap obviously ## \frac{l_{cap}}{l_{sphere}}=\frac{l_{arc}}{l_{circle}}=\frac{r*θ}{r*2π}=\frac{θ}{2π} ## But according to wikipedia formula...

This is not giving me the right answer! I have checked for errors like integer division and rounding, but can't find any. I am aware the comments are slightly inaccurate and they will be improved. But what's wrong with the actual code? //This method uses the trapezium rule to calculate the...

Hello! (Wave) I have written the following code in matlab: function v=uexact(x,t) v=sin(2*pi*x)*exp(-4*pi^2*t); end function [ex]=test3 h = 1/50; T=1/2500; x=0:h:1; t=0:T:1; ex=uexact(x,t); end I...

Homework Statement Give the IUPAC name for the following compound. Homework EquationsThe Attempt at a Solution However, the 4 and 7 were incorrect in the blanks. I'm not sure what went wrong.

I'm trying to stitch a ISO file together and failed. I used SFV Checker to varify every RAR files was Ok and then running latest winrar in WindowsXP_sp3; Winrar went through almost the entire process and gave me this " CRC failed in xxx.iso. The file is corrupt" at the end. It also showed no...

I am using an 1/8 HP motor with an SCR type dc drive and 1/4hp AC single phase control relays. I keep having a problem with welded relay contacts. Should I go to 1H/P relays? I don't know why I would have to being the HP of the motor is lower that the relay?

Hi PF! I am trying to solve a pde in MATLAB and started by using the generic code mathwork supplies and then augmenting for my purpose. After defining the function below and run the script, i can do anything to the ##f## and nothing changes. I can literally delete the line and still I receive...

Hey guys, I am working with a couple Netburner PK70 controllers and can only access one of them via Ethernet, but the other one (which has been formatted by the previous person on this project) Can't seem to be accessed by any of the Netburner software, I am currently running Advanced IP...

I http://www.pentalift.com/lift-tables/scissor-lifts&multi-stage.php. It works fine, when a single person is in the lift, but when 2 people of average weight are in the lift it will not go up properly. We haven’t exceeded the rated maximum capacity of the lift platform. It seems like it does not...

Hello! I have been trying to make a simulation and it doesn't quite work right, don't exactly know why. I have two questions! 1. Acceleration I have been trying I need a formula that uses. frames till full speed (f) (if framerate is 60fps and this value is 60 then player is at full speed...

I'm sorry for posting this another thread, but I accidentally posted under to wrong forum initially and could not figure out how to delete it :-(1. Homework Statement Find the missing isotope: Iodine-127 (n, alpha) My answer is Sb- 122 but it was wrong. Also, how would I go about finding the...

currently i need to turn on my IGBT. i measured Vge, it shown 8.25V, but my design requirement of Vge is 15V. i did some research, do i need to add in parasitic capacitances to my IGBT??

I am frustrated because although I put in the symbol for \sqrt{x} it doesn't translate it to the symbol. How can I get the **** thing to do that?

i have set up the circuit, but i do have some problem that i can't figure it out.. my frequency requirement is 20khz, i do follow the formula that the data sheet given, base on my oscilloscope, it shown 10khz.. capacitor voltage is 0.01 micro. resistor value is 5.5k ohms. when i connect the...

Homework Statement Constructing a NAND gate as an inverter. Homework EquationsThe Attempt at a Solution I've attached the image at my attempt to construct the circuit. The output is always on, which it should be except when both inputs are zero. Could someone explain what I am doing wrong...

Hello Engineers, while simulating transformer core losses in transient Maxwell sollution, I have got an error: Current leak to the air. does anyone ahev idea to solve this problem Thank you

I need to design a pwm circuit, i using the circuit from internet that i attached it.. freq is 20khz which is my requirement and 15v to power up the tl494.. there is no response when i connect potentiometer to it... waveform is attach can anyone give me advice?

I am working on a system that uses capacitance sensor probes, the system components are the probe, triaxial cable with LEMO connectors, BNC cable, oscillator, and a demodulator. I have had some trouble finding ways to troubleshoot the system other then basically testing continuity. Are there any...

Hi PF! So in mathematica I am trying to see if a function converges so I type: SumConverge[2/(n*Pi) Exp[-n^2*t] Sin[n x], n] All mathematica does here is echo back what I typed in. Is something I'm doing wrong? Thanks!

How would one construct a graph, like the Petersen graph, in LaTeX? Is there a good package to use for it? Edit: I should mention that I'm having trouble using instructions (which are not always consistent) that I'm finding on Google.

I have MATLAB R2013a. I am wondering why dmcode will not work.

Homework Statement I'm having a bit of trouble understanding something from this: http://gyazo.com/88a466b57d8516d2df1b12008947be43 Homework Equations The Attempt at a Solution I understand how to get the components of reaction at ##A## as well as the tension in segment...

Can anyone tell me what is alarm loging? I m working on a gas turbine,there is a problem in its controller.my instrument fellow told me that alarm loging is not working,I m from mechanical engineering background. Thanks in advance

Hi, I recently designed a PCB in EAGLE, and I got it manufactured and I had all the pieces Sufrace Mounted on it, put it in the oven, everything seems fine and dandy, but I already killed 3 LEDs because of some weird thing going on. I have 5 different LEDs conneced to my circuit, the leds run...

Hi, Recently, I made a batch of smoke bombs using potassium nitrate, sugar, and baking soda (to regulate reaction speed). My first batch took about four days to dry which seemed odd, however, they produced a fair amount of smoke. For my second batch, I decided to put the potassium nitrate I...

I'm trying to plot the evolution of a simple harmonic oscillator using MATLAB but I'm getting non-sense result and I have no idea what's wrong! Here's my code: clear clc x(1)=0; v(1)=10; h=.001; k=100; m=.1; t=[0:h:10]; n=length(t); for i=2:n F(i-1)=-k*x(i-1)...

Hello, I am trying to use some functions in MathCad given in my thermodynamics textbook to calculate thermodynamic properties. I attached the functions below. I try using them and then I get an error saying too many commas I just type in: MCPH(T1,T2;A,B,C,D)= of course with numerical...

I need some help with this problem. My housemate, a computer-illiterate lady who uses her daughter's old laptop solely to browse the internet, last evening wanted me to help her figure out how to (illegally) stream the Academy Awards Ceremony. I found a link but it wouldn't play on her Google...

https://www.physicsforums.com/attachment.php?attachmentid=65907&stc=1&d=1390369310 I've been stuck on doing my revision on this problem. The equation of the virtual work, from what I deduce is [du = 0] -Pdx + mg dh However the answer given is...

ok I wrote my own FFT class and I now have MatLab on my computer. I am comparing my code to mat-lab. so my test i used it this : for (int y = 0; y < 100; y++) { double temp8 = (2D * (Math.Sin(2D * Math.PI * 4D * (double)y / 100D)))...

Homework Statement i am study for a physics test and i think my physics teacher gave me the wrong equation for shear stress Homework Equations she gave me F=Δx/l *A The Attempt at a Solution

I know this is a simple problem but new at it. answer not in book so hope correct.

I have the XRD image of a PZT thin film. While trying to analyze it with JADE software I can not find the proper space group.So it is not giving me the answer I am looking for. I assumed the crystal system to be cubic.

We are given a velocity vs. time graph. It starts at 15 m/s at t=0 and goes to -10m/s at t=4 then it goes from -10m/s at t=4 to 15m/s at t=10 and we are told to find the postion after t=10 I first found the slope of the first segment which was -6.25. so I did ∫-6.25t+15 dt from 0 to 4 and...

SO I ordered the axe026 serial preograming cord to use with my picaxe 08m2. To plug it into the usb I am useing a usb to serial converter. But it's not working at all! I know my program is right but do I need a special driver? I downloaded the driver for the 026 AND 027, neither are working

Hello, I am trying to make an audio amp on my breadboard, for fun I guess. But it's not working! I am running off of this circuit of the lm1875...

So I want to make a solar usb charger but am having some problems that i do not understand. I know that usb is 5v at 1 amp-ish and so I took 4 rechargable AAs and was getting just over 5v. I want to have the solar pannel charge the batteries when there is nothing being pluged into the usb...