need help please  - Page 1
Forum section: electronics / testgear

author: defender
author_rank: Newbie
timestamp: June 15, 2014, 03:15:41 pm
content: hello>how do i set oscilloscope for the following:Set up a scope to monitor and sample the output( from current probe ) with sample-time of 200 msec and sample-spacingof 400 microsecfor a total of 500 counts ( count=1 thru 500)thanks,

author: Bored@Work
author_rank: Super Contributor
timestamp: June 15, 2014, 03:18:04 pm
content: When is that homework due? And do I get the credit points for the homework when I do it for you?

author: FrankBuss
author_rank: Unknown
timestamp: June 15, 2014, 04:04:34 pm
content: I wonder what scope they are using where you can setup the sample-spacing individually, with a given sample-time, assuming you want one full screen width for the sample-time. And unless you are in some special sampling mode, sample-spacing is the same as 1/samplerate anyway, so why the fancy name which I had to Google? Doesn't sound like a practical homework where you can learn something for your work later.

author: free_electron
author_rank: Super Contributor
timestamp: June 15, 2014, 04:14:51 pm
content: Without knowing what is the brand and model of the scope it is hard to say.We're not going to write a manal for all possible scopes out there.The question is bullshit anyway. Sample time 200 milliseconds (400 microseconds time 500 samples is 200 milliseconds.). Teacher is talking out of his ass confusing everybody. There is no need for this superfluous confusing information. It is ballast and can be construed as a trick question. Trick questions should be illegal in education. It's already hard enough conveying knowledge in a clear manner.Sample time is for a screen, so total sweep time. There are 10 divisions on a screen. 200 milliseconds to traverse, at 10 divisions means : Set the timebase at 20millisecond per division.If the screen is 500 points wide every point will be 400 microseconds apart.Now, As for the 500 points.. That's gotta be the crappiest scope in the world. Even the very first digital scopes had 4k sample points...

author: defender
author_rank: Newbie
timestamp: June 15, 2014, 06:15:35 pm
content: thanks for reply>the oscilloscope used is TEK TDS460 with TCP202 current probe.here is the full test for for the electronic module i have to run.Set up a scope and a current sensingdevice to monitor and sample the outputcurrent pulses at J1-11 with sample-timeof 200 msec and sample-spacing of400 microsec for a total of 500 counts(COUNT = 1 thru 500).Connect a 1 ? resistor between J1-11and J1-12, and capture the first 200msec of output waveform at J1-11(COUNT = 1 thru 500). Capture the first50 microsec of output waveform afterthe pulsed DC output at J1-11 rises to3.0 A (positive slope).Remove the resistor between J1-11 andJ1-12.For COUNT = 1 thru 500, and whilecurrent measured at present COUNT isgreater than 3 A, do the following stepswith the initial value of TOTAL set at 0:(1) Record the currentmeasured at presentCOUNT as CUR(2) Calculate TOTAL = TOTAL+ (CUR * CUR)Calculate TIME as follows:TIME = (COUNT - 1) * 0.0004Calculate TOTAL as follows:TOTAL = TOTAL / (COUNT - 1)Calculate pulse ENERGY as follows:ENERGY = TOTAL * TIMEthanks

author: HighVoltage
author_rank: Super Contributor
timestamp: June 15, 2014, 06:22:17 pm
content: Agilent has a pretty good educational powerpoint presentation for beginners.Type this in google, it is the first link:"Scope_Fundamentals_for_EE_Students"May be this helps you understanding the basics.

author: rf-loop
author_rank: Super Contributor
timestamp: June 15, 2014, 06:27:59 pm
content: Quote from: free_electron on June 15, 2014, 04:14:51 pmThese are not at all very first digital scopes.HP54501A, 54502A 501 sample points.HP54200A/D 1001 sample points.Andfor just same work what they have usedin '80-'90 they are also today exactly as good as they have been new. (but not for many today needs)And today some 2GSa/s scope may use example 28 points sampling buffer with 1ns/div setting.What is crap - it depends...