Oscilloscope triggering from Function Generator - Page 1
Forum section: electronics / beginners

author: DedoDado
author_rank: Newbie
timestamp: March 10, 2022, 08:03:59 am
content: Hello!I'm interested in how to operate an oscilloscope trigger using a function generator.(Siglent SDG1032X function generator + SDS 1202X-E DIGITAL OSCILLOSCOPE).What I actually want to achieve is testing the components (capacitors and inductors) using a square voltage wave.Thanks in advance!

author: Romualds
author_rank: Contributor
timestamp: March 10, 2022, 02:33:36 pm
content: Quote from: DedoDado on March 10, 2022, 08:03:59 amIf I got you correctly, you can just trigger your oscilloscope from first edge of the the same pulse you use for testing.

author: CaptDon
author_rank: Super Contributor
timestamp: March 10, 2022, 04:13:56 pm
content: Many function generators have a separate trigger output, connect that to the external trigger input of your scope. If the scope is multi-channel use channel one connected to either the trigger output of the sig gen or the actual output of the sig gen and use channel two to investigate your circuit under test. How do you own both a scope and a sig gen and not know how to trigger the scope properly?Kind of like owning a car and not knowing how to open the door to get in??

author: MuseChaser
author_rank: Contributor
timestamp: March 10, 2022, 04:31:09 pm
content: Quote from: CaptDon on March 10, 2022, 04:13:56 pmIn defense of the OP, I'll answer your questions from my perspective. I own the same scope, purchased a few weeks ago, because I want to learn. I started at ground zero, having never touched a scope before. I'm getting better with it, and have used it to do some diagnostic work on a Dynaco SCA80Q, but I couldn't have answered the OP's question. We all start somewhere. I'd say opening the door to a car is more like unpacking the scope from the shipping box. Starting the car might be like hitting the power button of the scope to turn it on. Actually using the scope is more complicated than driving a car, and we all practice quite a bit of driving before becoming experienced, competent, safe drivers. Maybe give the guy a break? I know I could use one...

author: Electro Fan
author_rank: Super Contributor
timestamp: March 10, 2022, 05:38:29 pm
content: Quote from: MuseChaser on March 10, 2022, 04:31:09 pmWe all start somewhere.

author: CaptDon
author_rank: Super Contributor
timestamp: March 11, 2022, 05:22:52 pm
content: Well, I guess it is sad that 'todays scopes' don't come with the fantastic operator manuals like the Tektronix stuff used to have that had page after page after page of diagrams showing waveforms of various types and the CORRECT triggering methods to be used. They also thoroughly explained the pitfalls of improper trigger points. R.T.F.M. were the words spoken back in the days when electronic service instruments came with books you could open up on the bench and look at instead of stupid PDF CD's that require more needless junk to clutter your work area just to view the manual. My TDS644B came with Operators Manual, Programmers Manual and Service Manual all in 3-ring binders, all with tons of 'How-To' illustrations.

author: TimFox
author_rank: Super Contributor
timestamp: March 11, 2022, 05:38:40 pm
content: This is the "Beginners" section, where one should not assume previous experience from the posters.Back in grad school, I was popular as a lab partner because I knew how to trigger oscilloscopes.

author: Ground_Loop
author_rank: Frequent Contributor
timestamp: March 11, 2022, 06:01:55 pm
content: Quote from: CaptDon on March 10, 2022, 04:13:56 pmMore of the same valuable insight. Made me verify that I know how to open my car door.

author: CaptDon
author_rank: Super Contributor
timestamp: March 11, 2022, 09:05:34 pm
content: At the beginning of the beginners forum is endless information on scopes, their types, their uses, etc. etc. I think before I bought a scope and function generator (if that is what the O.P. did) I would have investigated a wealth of knowledge on scope functions and uses, decided I needed one and be somewhat already versed in how I was going to use it, how to use it and why. The question how do I trigger from a function generator.....well, how do you trigger from ANY signal source? Then we have to ponder, is it a multi-channel scope? Can one channel be used as the trigger and another channel as the 'investigative input'? Does the function generator have the typical 'Trigger Out' connection? Does the O.P. have BNC tees to trigger from the signal output instead of the trigger output? Does the scope have an Ext Trig In connection? Too many variables to define the answer without farther information. How do I get to Kathmandu? All kind of depends on the starting point I guess?

author: Electro Fan
author_rank: Super Contributor
timestamp: March 12, 2022, 01:29:18 am
content: Quote from: CaptDon on March 11, 2022, 09:05:34 pmdepends on the starting point

author: Simon
author_rank: Unknown
timestamp: March 12, 2022, 02:21:31 pm
content: This question will never get any sensible answers as it's invalid. You don't "test" components with an oscilloscope. Suggest the author starts again in smaller chuncks.

author: rstofer
author_rank: Super Contributor
timestamp: March 12, 2022, 08:44:39 pm
content: I imagine you could check capacitance to some degree of accuracy just watching the charge curve. I do that with my Analog Discovery 2 all the time. My favorite demonstration is just a 0.1 ufd ceramic capacitor and a 10k resistor. Some scopes do Bode' Plots but mine doesn't. The AD2 does them quite wellInductors can be tested using a resonant circuit:https://www.testandmeasurementtips.com/how-to-measure-inductance/Transistor curve testers for use with a scope are all over the Internet.https://circuitcellar.com/research-design-hub/create-your-own-i-v-curve-tracer/Document page 49 and onward for more than 30 pages, the User Manual discusses triggering:https://siglentna.com/USA_website_2014/Documents/UserManual/SDS1000X&Xplus_UserManual_UM0101X-E02A.pdf

author: Simon
author_rank: Unknown
timestamp: March 12, 2022, 08:55:12 pm
content: Yes if you set up a test you can measure parts, but it almost sounds like the OP thinks they can test part "with an oscilloscope", the measurement will always be indirect like in your example of charge/discharge time of a capacitor - with a known resistor of course.

author: TimFox
author_rank: Super Contributor
timestamp: March 12, 2022, 09:03:07 pm
content: Actually, in his post the OP said he wanted to test capacitors and inductors with a square wave. Assuming he adds a resistor to the circuit, his function generator and oscilloscope can give useful measurements.

author: Simon
author_rank: Unknown
timestamp: March 12, 2022, 09:40:52 pm
content: Well I don't quite see the connection in the two halves of the question. It's two questions:1) How do I set up the scopes trigger (usually it's default will do what is asked in Q2)2) How do I test a capacitor or inductor with an oscilloscope and a signal generator (using other components).1, is about the equipment, 2 is about using the scope in a certain context.

author: rstofer
author_rank: Super Contributor
timestamp: March 12, 2022, 09:53:31 pm
content: When CharlotteSwiss bought her scope, she didn't even have a signal generator. In that thread we used the compensation square wave for a number of learning exercises. There's a lot of good fun in that thread after she buys the scope in Reply 150. I had never used a scope to get the integral of sin(x) over some period not equal to 2*pi. Outstanding stuff! But it's 37 pages of replies...https://www.eevblog.com/forum/beginners/what-an-oscilloscope-recommended-for-a-woman-passionate-about-electronics/msg3100087/#msg3100087Charlotte decided to start on page 1 of the User Manual and learn what every control does. Most people don't even look at the manual, she wanted to try everything!