# Weird Oscilliscope Waveform on new device.

#### ben sorenson

Joined Feb 28, 2022
10
Hello, I am new to building electrical devices, I am in the middle of building a power supply and found this as my output signal. Any Speculation would be appreciated. Thank you.

#### Ya’akov

Joined Jan 27, 2019
5,659
Welcome to AAC.

That is a sine wave, but the scope's timebase is too short to display it properly, and it is also not triggering properly.

Make the time base longer and adjust the trigger and it will look much better.

[EDIT: had things backwards there for a moment]

#### Ya’akov

Joined Jan 27, 2019
5,659
Here's the same sort of thing on a more modern scope.

Trigger adjusted properly, timebase too short

There may be times when you want to fill the screen with one cycle of your waveform. On a CRO (Cathode Ray Oscilloscope) like yours, too would shorten the timebase to "stretch out" the waveform. On a modern DSO (Digital Storage Oscilloscope) there will be a facility to "zoom" in on the waveform and move along it.

Normally though, you'd expect the timebase to be set to show a few cycles not just one. Timebase is may be labeled "horizontal" because it affects the horizontal axis, which is time. The "vertical" would be the height of the wave.

#### ben sorenson

Joined Feb 28, 2022
10
Welcome to AAC.

That is a sine wave, but the scope's timebase is too long to display it properly, and it is also not triggering properly.

Make the time base shorter and adjust the trigger and it will look much better.
Here's the same sort of thing on a more modern scope.

View attachment 261829

View attachment 261830
Trigger adjusted properly, timebase too short

View attachment 261831
There may be times when you want to fill the screen with one cycle of your waveform. On a CRO (Cathode Ray Oscilloscope) like yours, too would shorten the timebase to "stretch out" the waveform. On a modern DSO (Digital Storage Oscilloscope) there will be a facility to "zoom" in on the waveform and move along it.

Normally though, you'd expect the timebase to be set to show a few cycles not just one. Timebase is may be labeled "horizontal" because it affects the horizontal axis, which is time. The "vertical" would be the height of the wave.
Here's the same sort of thing on a more modern scope.

View attachment 261829

View attachment 261830
Trigger adjusted properly, timebase too short

View attachment 261831
There may be times when you want to fill the screen with one cycle of your waveform. On a CRO (Cathode Ray Oscilloscope) like yours, too would shorten the timebase to "stretch out" the waveform. On a modern DSO (Digital Storage Oscilloscope) there will be a facility to "zoom" in on the waveform and move along it.

Normally though, you'd expect the timebase to be set to show a few cycles not just one. Timebase is may be labeled "horizontal" because it affects the horizontal axis, which is time. The "vertical" would be the height of the wave.
Thank you guys so much for your reply's. I build engines and diagnose automotive electrical faults for a living and have started building circuit's as a hobby because my brain is peaked out on the auto stuff. Sometimes I feel stupid for asking basic questions but then I remember
when I was 18 some old guy at the corner mechanic shop tought me the skills that would carry me down the road for the rest of my life so...thanks guys.

#### Ya’akov

Joined Jan 27, 2019
5,659
Thank you guys so much for your reply's. I build engines and diagnose automotive electrical faults for a living and have started building circuit's as a hobby because my brain is peaked out on the auto stuff. Sometimes I feel stupid for asking basic questions but then I remember
when I was 18 some old guy at the corner mechanic shop tought me the skills that would carry me down the road for the rest of my life so...thanks guys.
Don’t ever worry about asking questions. There are many people here who will be happy to answer them. As long as you do your part of providing enough information and carefully read the answers which will often have very specific questions for you, iyoull always be welcome.

#### ben sorenson

Joined Feb 28, 2022
10
Don’t ever worry about asking questions. There are many people here who will be happy to answer them. As long as you do your part of providing enough information and carefully read the answers which will often have very specific questions for you, iyoull always be welcome.
Awesome! Thank you again. Another quick question. On my Oscilliscope Leader 15MHZ. There is a ground wire attached to the probe, also a port on the machine for ground. When measuring AC any idea where I clip the ground side to? Do I connect it to the neutral side of the circuit?

#### Ya’akov

Joined Jan 27, 2019
5,659
Awesome! Thank you again. Another quick question. On my Oscilliscope Leader 15MHZ. There is a ground wire attached to the probe, also a port on the machine for ground. When measuring AC any idea where I clip the ground side to? Do I connect it to the neutral side of the circuit?
You should it connect your scope to the AC mains without knowing more about scopes and having a good reason. You can use a transformer to reduce the voltage and isolate the scope and in that case it would make only a subtle difference which wire you connected to which.

#### MrChips

Joined Oct 2, 2009
26,089
What is the model number of your oscilloscope?
Show us a photo of the whole front face. We want to see the controls and the markings as well.
Then we would be able to tell you how to set up your scope.

You want to set the HOR TIME/DIV to about 10ms.
Simply touch your finger on the tip of the probe and observe the waveform.

After that we will instruct you on what to do with the ground clip.

#### Ya’akov

Joined Jan 27, 2019
5,659
What is the model number of your oscilloscope?
Show us a photo of the whole front face. We want to see the controls and the markings as well.
Then we would be able to tell you how to set up your scope.

You want to set the HOR TIME/DIV to about 10ms.
Simply touch your finger on the tip of the probe and observe the waveform.

After that we will instruct you on what to do with the ground clip.
I am making a not completely wild guess this is the scope he has:

Not a bad scope to start with. It's not overly complicated but has all the controls needed to learn the principles and operation of an oscilloscope. 15MHz is more than enough bandwidth at this point. I don't even have a guess at what he has for a probe, though.

#### iggnator

Joined Jan 30, 2019
15
Awesome! Thank you again. Another quick question. On my Oscilliscope Leader 15MHZ. There is a ground wire attached to the probe, also a port on the machine for ground. When measuring AC any idea where I clip the ground side to? Do I connect it to the neutral side of the circuit?
This is worth a watch on youtube to understand grounding of your oscilloscope and playing with your AC power system:

#### AnalogKid

Joined Aug 1, 2013
10,054
Doesn't look like a mis-triggered sine wave to me. My first guess would be line-freq ripple.

Please post the schematic of your circuit, and indicate on it where the scope probe(s) were attached. Without a schematic. we have *zero* information about the signal you are displaying.

ak

#### drjohsmith

Joined Dec 13, 2021
394
Doesn't look like a mis-triggered sine wave to me. My first guess would be line-freq ripple.

Please post the schematic of your circuit, and indicate on it where the scope probe(s) were attached. Without a schematic. we have *zero* information about the signal you are displaying.

ak
I do think though the signal would look good as an old TV Scifi background,

#### Audioguru again

Joined Oct 21, 2019
4,680
I decreased the scan rate to show a few waveforms and I synced it.

#### Attachments

• 331.4 KB Views: 14

#### drjohsmith

Joined Dec 13, 2021
394
Hello, I am new to building electrical devices, I am in the middle of building a power supply and found this as my output signal. Any Speculation would be appreciated. Thank you.View attachment 261825View attachment 261826View attachment 261827View attachment 261825View attachment 261825View attachment 261826View attachment 261827
View attachment 261825View attachment 261826View attachment 261827
May be I missed it
but what is your volts per division. and time base per division set at ?

#### AnalogKid

Joined Aug 1, 2013
10,054
S.c.h.e.m.a.t.i.c. . . . .

To paraphrase Rear Admiral Joshua Painter,

"Engineers don't take a dump, son, without a schematic."

ak

#### ben sorenson

Joined Feb 28, 2022
10
I am making a not completely wild guess this is the scope he has:

View attachment 261856
Not a bad scope to start with. It's not overly complicated but has all the controls needed to learn the principles and operation of an oscilloscope. 15MHz is more than enough bandwidth at this point. I don't even have a guess at what he has for a probe, though.
Yes, that is my scope, picked it up for $80 because my digital one was acting goofy and needed something to compare it against that didn't go through the adc process. What do you think about this Waveform? I can see it is like a sine wave but what about the periodic fuzzys in the center? #### Attachments • 1.3 MB Views: 6 • 1.2 MB Views: 6 • 1.4 MB Views: 6 #### Ya’akov Joined Jan 27, 2019 5,659 Yes, that is my scope, picked it up for$80 because my digital one was acting goofy and needed something to compare it against that didn't go through the adc process. What do you think about this Waveform? I can see it is like a sine wave but what about the periodic fuzzys in the center?
What that looks like to me is an disconnected probe picky up the mains and switching hash around it. I see that triangle wave a lot, and there can be all sorts of periodic glitches in it from power supplies in equipment nearby,

This psychedelic mess is from the general hash and the two PWM dimmed LED task lights on it. The second shot is zoomed in, see the funky PWM waves?

The important question is, what is the scope probe connected to? What do you expect to see on the scope?

#### Audioguru again

Joined Oct 21, 2019
4,680
Why do you think the distorted triangle waveform is a sinewave?
What are the 'scope inputs connected to and what is the measured AC voltage?