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I just got my first scope, it's an old analog, 2-channel, seems to be fine but what do I know.
Here's what I've done so far:
Before powering on I set the knobs per the manual.
Powered it up, said ooh and ahhh.
Found the beam!
Saw that I could read DC 5 volts on each channel!!
The beam is nice and bright and straight at DC 5V!!
(hard to tell but it was exciting)
Now what? I placed the probe on my finger tip. EKG???
I think it was picking up 60Hz on the probe cable but don't know.
I found the 500ms pp, 1kHz probe compensation port, found the small screwdriver and adjusted the probes on each channel
(thanks to w2aew)
So I think the scope's okay, but what I think's not backed by anecdotal or empirical evidence.
It's only what I think and I don't always believe what I think.
(does anyone?)
What other things can I do to test the scope?
How can I create some interesting tests for this scope with what's at hand?
My lab consists of a DMM and an oscilloscope and a digital soldering station plus some minor tools.
I have a salvaged PS from a dvd player that has DC -12V, 12V, 5V outputs.
I have a breadboard and various resistors, transistors, caps, motors, transformers salvaged from a tv/video combo and a dvd player.
(I have the solder burns to prove it!)
Here are the probes I just got:
https://www.eevblog.com/forum/buysellwanted/good-ebay-deal-buy-it-now-scope-probes-$8-99-free-shipping-in-us/
I've got a pdf of the manual but it's a pdf of jpg images and the aspect ratio of the images doesn't fit my reader and so I need to convert that which is a PITA.
I really need to convert it into text and a proper ebook but that leads me to tesseract and on down the rabbit hole I go. -
Hook your probe up to a switch mode power supply. Fiddle around with the settings until you get a nice steady trigger on all that gross noise!
If you go down the path of wanting to make low noise measurements, you'll eventually want to buy some spring tips for your probes (reduces the loop area which picks up 60Hz noise).
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I think it was picking up 60Hz on the probe cable but don't know.
60Hz means 16.667 mS per cycle. So set your horizontal scale for 10 mS/div, and you should see a bit more than one and a half divisions per cycle, if you're seeing 60Hz AC. You probably are -- 60Hz gets picked up easily when a probe is unconnected.
Resist any temptation you might have had to connect the probes directly to AC mains to study the waveform.
If you have any battery operated audio devices, radios, CD players, mp3 players, etc., try placing the probe across the speaker output. If it's random audio, and not a pure tone, you'll see oscillations, but they'll vary as the audio varies. You might have to set the trigger to be free-running to see the trace.
If you have a computer with a sound card, search the web for "sound card signal generator". You can easily get your computer to generate waveforms at audio frequencies. Quality will depend on your soundcard quality, but it should at least be enough to get some practice using the scope at different frequencies and amplitudes, and you can play with trigger levels to better understand how they work. It should probably allow you to do simple experiments like testing the voltage vs current for various reactive components at various frequencies. -
Congrats on your first scope. There are a few things to try first for fun.... Hook up to your cellphone or pc audio and find oscillofun or youscope demos on the Web (flac or wave best, not mp3). Set it up in xy mode for those. Also you can find wave generators for pc to generate lissajous patterns. You can also pick up a gabotronics xprotolab to make various different waves.
If you want to try programming an arduino with resistor ladders you can make stepped outputs (DAC) to draw stuff. Basic electronic fun would include looking at RC filters, how caps alter your 1k calibration signal, and playing with component tester (if your cro doesn't have one, you can build one fairly easily). The tester simply cycles from -voltage to +voltage across the x while checking component on the y. Then you see led response curves, diode L, and so on. You can use a saw wave generator.
I am sure there is a book somewhere with a bunch of easy projects to build just to display and learn on a cro.
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Hook your probe up to a switch mode power supply. Fiddle around with the settings until you get a nice steady trigger on all that gross noise!
I don't have a switch mode PS. But will try to find one locally.QuoteIf you go down the path of wanting to make low noise measurements, you'll eventually want to buy some spring tips for your probes (reduces the loop area which picks up 60Hz noise).
I think the probes have spring tips but not 100% sure what they are, the probes I have come with removable tips that contain a retractable hook that is spring loaded. Are we talking about the same? -
What's the model? It likely has a test clip for a square wave you can use to adjust the probe compensation.
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60Hz means 16.667 mS per cycle. So set your horizontal scale for 10 mS/div, and you should see a bit more than one and a half divisions per cycle, if you're seeing 60Hz AC. You probably are -- 60Hz gets picked up easily when a probe is unconnected.
This makes sense. I noticed in videos the 60Hz AC signature. I wasn't able to do much with it, But I will revisit that later.QuoteResist any temptation you might have had to connect the probes directly to AC mains to study the waveform.
Good advice and no problem here. I recently blew the 15A breaker probing where no one had probed before. I was testing the mains input on my salvaged power supply. My new DMM probe tips are no longer new looking. The soot is a reminder. Emory cloth restored them from jagged peaks back into a tip albeit a little shorter. It was last the thing I did before calling it a day. Pure stupidity. There I was standing in the dark. Mostly concerned with my new meter of course. Then I started to think about the breaker. It was a new breaker and performed well and isolated the stupidity to the "lab". The meter survived no problem!QuoteIf you have any battery operated audio devices, radios, CD players, mp3 players, etc., try placing the probe across the speaker output. If it's random audio, and not a pure tone, you'll see oscillations, but they'll vary as the audio varies. You might have to set the trigger to be free-running to see the trace.
This I can try! I have an old mp3 player that I secretly hope will release it's magic smoke. But it may prove hard as this thing never got the smoke to begin with. It's a Long Duck Dong model.
If you have a computer with a sound card, search the web for "sound card signal generator". You can easily get your computer to generate waveforms at audio frequencies. Quality will depend on your soundcard quality, but it should at least be enough to get some practice using the scope at different frequencies and amplitudes, and you can play with trigger levels to better understand how they work. It should probably allow you to do simple experiments like testing the voltage vs current for various reactive components at various frequencies. -
Perfect test use a small switch mode power supply(cell phone charger). 1st set scope to dc coupling find the trace. Then do a rise time measurement.
After set to ac coupling and check the ripple. -
Perfect test use a small switch mode power supply(cell phone charger). 1st set scope to dc coupling find the trace. Then do a rise time measurement.
After set to ac coupling and check the ripple.
Ok I do have a switch mode power supply. (cellularmitosis I lied) I will try this as well. -
If you have any battery operated audio devices, radios, CD players, mp3 players, etc., try placing the probe across the speaker output. If it's random audio, and not a pure tone, you'll see oscillations, but they'll vary as the audio varies. You might have to set the trigger to be free-running to see the trace.
I took it for granted that I'd figure out what you meant once I got in front of the scope. But I gave it a shot and I only see the 60Hz I'm bathed in here.
What does "set the trigger to be free-running " mean? -
He's talking about "auto" mode on triggering. You will always have a trace on the display even if not triggered.
Check out alan w2aew's "Scopes for Dopes" video
I've watched it several times.
Also give use some pictures of your set up
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Check out alan w2aew's "Scopes for Dopes" video
I've watched that once and need to watch it again. The problem I had with it was that questions came in from the local audience which I couldn't hear and then the conversation changed toward that question and I get a bit lost.
Yeah I have it on auto mode.
I need the "Oscilloscopes for those that like to learn by doing - Step-by-step and hands-on".
I'll figure it out, the learning curve's steep but it's easy to keep climbing because I enjoy it.
I am converting the manual (PDF-- all small jpg images) into an ebook. I could not bring myself to print out 400 pages.
Once I get the ebook on my reader than I can go through the manual and get more familiar in front of the scope. -
Make this!
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get yourself a few 741 op amps, theyre pretty well outdated so i cant see them being more than 5-10 cents a piece, and make up a simple wave generator. gives you practice with building circuits and using the scope.
http://www.ody.ca/~mgenovy/opcct2.GIF
http://2.bp.blogspot.com/-jfF6l1z-fBk/UHbhpIRqA4I/AAAAAAAAAN8/0K4Ygc8WkhE/s1600/A%2BSimple%2BFunction%2BGenerator.jpg
(teh 1458 is just 2 ganged 741 op amps in one ic)
a 555 will work too, another cheap ic.
http://www.seekic.com/uploadfile/ic-circuit/2011420212730799.jpg
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I think the probes have spring tips but not 100% sure what they are, the probes I have come with removable tips that contain a retractable hook that is spring loaded. Are we talking about the same?
Sorry, what I meant was a "ground spring".
Start watching at about 0:55
They really work! -
Sorry, what I meant was a "ground spring".
I see, interesting, I will try that out. -
Make this!
I haven't looked at the schematic yet but that could be fun. -
get yourself a few 741 op amps, theyre pretty well outdated so i cant see them being more than 5-10 cents a piece, and make up a simple wave generator. gives you practice with building circuits and using the scope.
I didn't find any for 5-10 cents but it sounds like an economical project still. -
Use your 1khz square to drive an RC circuit and display output of both square and modified rc output on both channels. Using calculator here: http://www.pronine.ca/rccir.htm
You will find combinations of RC that give a nice curve in the time required of 1 kHz (about 0.5 ms). R value about 100 ohm with 2 microF, or 1kohm with 200 nF, or try some other combination if you can find standard values for components.
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If I had a scope (still trying to source a not too pricey one), I would build up some 555 timer circuits and fiddle with parameters and watch would happen.
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Hi, what oscilloscope model did you get?
For testing the scope functions the calibration signal is a good start, you can measure rise time, frequency, amplitude... more or less acurate
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I like deth502's first schematic very much
, there you have 3 different waveforms to play with.
Here is also a nice link to a website about such oscillators:
http://www.onegentleman.biz/Hardware%20Design/Op-Amp%20Oscillators/2013-Op-Amp%20Oscillators.php .
And here is something nice experiment to play: if you have a little flashing LED candle light
you could try to hook your probe to it and look whats going on :-).
Crack the top part open and hook the ground clip to the negative LED pin and probe the other 2 pins. You will get some square-wave signal (50% duty cycle to save energy) and when you make your timebase slow enough, you will see some dc offsets (spikes) from time to time - this makes the LED flicker.
Have fun playing with your oscilloscope :-). -
Use your 1khz square to drive an RC circuit and display output of both square and modified rc output on both channels.
By "drive" you mean to connect the 1kHz output to the external trigger BNC input?
Then connect one channel also to the 1kHz square and the other channel to the RC circuit with the probe in series?
i.e. probe tip to the RC output and the ground clip to where???
I feel a bit clumsy as I usually just try stuff out and see what happens but I don't really want to do any permanent damage to anything. -
I think edy is talking of a filter like this:
You can build it up on a breadboard and use a variable resistor (and variable cap) to play with the effects it does (low pass/high pass as the name says).
Doesn't have anything to do with the trigger input
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Ground is for example at the outside of the scopes BNC connectors (sometimes there is also a little ground loop/GND connector at the front, depends on your scope) and the signal is obviously on the scopes test-signal output :-). You could hook the RC circuit to them and the probe and it's GND clip to the output of the circuit (see the bottom line in the schematics as the ground).
And you hook the second probe directly to the test-signal output.
So you can compare both to each other and vary the resistor and look on the effects the RC circuit does.
Asking this questions I would really not recommend you to hook anything of your scope to something like a switch mode PS as it was suggested some comments before (or something other not battery driven), unless u are a little more experienced in using your scope , or you really might damage something (or yourself).
There is also a nice (longer) video from w2aew at the top of the Forums beginner-section that can make you a little more familiar with the basic function(s) and components of a scope.
Hope this helps :-).
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Hi, what oscilloscope model did you get?
It is a very old Tektronix 2215A, but it seems to be working properly. I have to admit that I don't get attached to inanimate objects to the degree that I see that some do here, but this scope has a certain set of qualities that I like. The knobs are damn fun! I like the time/div knob, it requires a firm purchase and has a feel that I don't recall encountering on any other device. When I first tried to adjust it I thought that I would either break it or it was already broken. But then I discovered it requires force. I hope these new digital scopes retain that feel, if not I don't know if I want one!QuoteFor testing the scope functions the calibration signal is a good start, you can measure rise time, frequency, amplitude... more or less acurate
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I like deth502's first schematic very much , there you have 3 different waveforms to play with.
Here is also a nice link to a website about such oscillators:
http://www.onegentleman.biz/Hardware%20Design/Op-Amp%20Oscillators/2013-Op-Amp%20Oscillators.php .
I am simlutaneously reading a DC/AC text book, converting the tek manual to an ebook and reading it*, looking for the parts mentioned so far, learning a breadboard (or some call protoboard), learning programming mCs (and what to buy) and putting my "lab" together (which means making space).
But I will soon have a chance to follow the schematics mentioned so far and try them and report back.QuoteHave fun playing with your oscilloscope :-).
I think I have such a candle, great ideas! And it is fun isn't it.
*Also reading a series starring the Posleen*
*if they made this into a movie it might disturb the masses. -
Yes, attach 1kHz calibration to scope channel 1.
Also attach 1kHz cal (split off from channel 1) to an RC filter, like the one shown in a previous post. For channel 2, attach one lead between the R and C and the other after the C as your ground, like the schematic shows. Hopefully this setup won't cause too much interference between the 2 channels.
Use R of about 100 ohm with C of 2microF, or if you multiply R by 10 to get 1kohm then divide C by 10 to get 200nF. If in doubt, use a RC time calculator and get something in the range of 0.5msec to get to about 90% rise time.
I also agree with a previous comment that if you are not experienced yet, stay away from any mains plugs or power supplies. Stick to battery powered stuff or a breadboard powered by a DC or AC power supply but be sure to figure out how to properly ground, so you don't blow yourself up or your scope.
There is a nice video by Dave regarding how ground works on scopes. You want to make sure you don't touch something you shouldn't and ground your high voltage circuit through to earth ground shared with your scope, shorting through your probes.