Is my oscilloscope broken? - Page 1
Forum section: electronics / beginners

author: d4n13l
author_rank: Regular Contributor
timestamp: July 27, 2018, 03:59:18 am
content: Hi everyone,I don't have much practice with the oscilloscope so I'm not sure if it's malfunctioning or I'm missing something, I'd appreciate some help.I have a rigol DS1054z and I'm trying to see how a capacitor charges overtime by putting it in series with a resistor. I set the oscilloscope to normal mode and set the appropriate scales. But when I press the run button, the status says run and the screen shows the normal background squares but I don't see the yellow voltage line as I see when using the auto mode. At first I thought it was a triggering problem so I pressed the force button and hear a sound but still I don't see the voltage line.I know it's measuring because I was just pushing buttons trying to make it work when suddenly I saw the voltage line (I set a time base of 20 sec) of what was previously measured so I know my setup is fine. This has happened 2 or 3 times, I've been at it for a while... For some reason it's not displaying the voltage line not sure if that's normal and I'm missing something really obvious or its malfunctioning, any ideas?

author: TERRA Operative
author_rank: Super Contributor
timestamp: July 27, 2018, 05:07:22 am
content: What's your voltage (vertical) scale set to, and what voltage are you using in your circuit under test?Also, is the vertical position set so the trace is on the screen?

author: d4n13l
author_rank: Regular Contributor
timestamp: July 27, 2018, 05:36:38 am
content: The voltage value per grid is 2V with a horizontal time base of 20sec (the charging of the capacitor takes 10sec) and I'm running the circuit on 5V. As for you last question, I just made sure the screen is centered before starting to measure...As I mentioned, I know its working because apparently for not reason the trace suddenly appears and its centered, when this happens I see the progress of the trace just fine. This also shows that the measuring is happening its just not displayed on the screen

author: ataradov
author_rank: Super Contributor
timestamp: July 27, 2018, 05:47:43 am
content: On long time bases the scope accumulates the data first and then displays it. It looks for a trigger condition.

author: d4n13l
author_rank: Regular Contributor
timestamp: July 27, 2018, 06:08:41 am
content: But it should display what has accumulated when you push the force button, doesn't it? When I do it the screen stays the same with no trace

author: ataradov
author_rank: Super Contributor
timestamp: July 27, 2018, 06:09:51 am
content: I don't think I even know where the force button is. Never used it in my life.

author: borghese
author_rank: Regular Contributor
timestamp: July 27, 2018, 06:11:34 am
content: Have you set the trigger level correctly? If you put the trgger on "line" the track should always be visible

author: d4n13l
author_rank: Regular Contributor
timestamp: July 27, 2018, 07:00:35 am
content: Ok I figured this out.. it was a newbie overlook after all.I was adjusting the vertical trigger to when the trace reached some mV but there is a second horizontal one in the middle of the screen I was overlooking. For the vertical one to work first the horizontal must be reached, but since it was in the middle of the screen and since I had 20sec /division it required a few minutes to be triggered, that's why it spontaneously appeared the trace after a while, also their behavior changes depending on the trigger mode. So, yeah..Thanks a lot everyone

author: alsetalokin4017
author_rank: Super Contributor
timestamp: July 27, 2018, 03:13:58 pm
content: Quote from: d4n13l on July 27, 2018, 05:36:38 amOK, that's good that you've got it solved. But is your scope setting really working to show you what you are looking for? If your cap takes 10 seconds to charge, and you are looking at it at 20 sec/div horizontally... you aren't seeing much detail. Here's a sample of a cap charge-discharge scopeshot, showing what the 1054z does with it:

author: d4n13l
author_rank: Regular Contributor
timestamp: July 27, 2018, 07:36:26 pm
content: It looks similar to that.. I think I misspoke before, the 20sec appear on the top left of the screen where your scopeshot has 10ms, I think that's the time for the whole screen. The manual says it represents the time per grid, which at first I interpreted it to mean per division. I'm a native Spanish speaker, sometimes I misinterpret stuff. Thanks for you interest though

author: alsetalokin4017
author_rank: Super Contributor
timestamp: July 27, 2018, 08:29:14 pm
content: No, the number appearing in top left in the "H" box is the time per division setting, NOT the time it takes for the whole screen. If you had "20 sec" here, then the whole screen takes 12 x 20 sec or 240 seconds. So no wonder you had to wait. Note also where I have the trigger set, near the leftmost edge of the screen, not in center.Quote from: ataradov on July 27, 2018, 06:09:51 amIt's the bottom rightmost button on the DS1054z panel.It's pretty important on the DS1054Z because the key sequence (trigger) MENU-MENU-FORCE-MENU, very fast, followed by Utility>System>System Info, is how you get to the full System Information screen where all the software and firmware are listed, plus startup count and time in use.You can also use it to force a trigger in Single Shot mode...