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Learning how to use an Oscilloscope

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Ron
 Ron
(@zander)
Father of a miniature Wookie
Joined: 3 years ago
Posts: 6856
Topic starter  

First of all, from here on it is called a scope as the other word is too long to keep typing.

I should get my new scope, a Rigol DHO802. It's been 50 years since I last touched a scope, and even then used it only a few times a year. I will need to learn from scratch. Another member suggested I chronicle my journey in case others benefit. This is the start.

So far, I have a book on order, a hardware board designed as a scope teaching device, and a few websites. I will locate a YT video or two along the way. If you are interested, either subscribe to this Topic or Follow me, but Following me will get you notified of all my other posts as well.

The board is called the Oscilloscope Tutor Module. It is about $35 CDN/$25 USD

I got mine at qkits.com, but shipping and tax made it $58.86. I also saw it for sale elsewhere for over $50.

I also plan on using 555 timer circuits, OpAmp circuits, and a small, inexpensive Signal Generator I previously purchased. I have seen references to using Arduinos, etc to create scope testing circuits and will do that as well.

That's it for now. If you would like to drop a reply to let me know you are subscribed or following, that will help me do a better job.

-30-

 

First computer 1959. Retired from my own computer company 2004.
Hardware - Expert in 1401, and 360, fairly knowledge in PC plus numerous MPU's and MCU's
Major Languages - Machine language, 360 Macro Assembler, Intel Assembler, PL/I and PL1, Pascal, Basic, C plus numerous job control and scripting languages.
Sure you can learn to be a programmer, it will take the same amount of time for me to learn to be a Doctor.


   
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Ron
 Ron
(@zander)
Father of a miniature Wookie
Joined: 3 years ago
Posts: 6856
Topic starter  

I didn't realize I needed a 9VAC adapter, so I have not started with the Tutor Board. After unboxing, I connected the probe to the built-in Probe Compensation Signal and adjusted the probe. I connected 9VDC to the Tutor Board and then connected the probe to a random point on the board. NADA was on the screen, so I pressed the 'AUTO' button, and voila, a signal. This button will be my favourite, I am sure.

The next thing I did was to use my new printer to print the instruction manual. It is 238 pages or about 1/2" double-sided (I was tempted to print it 2up double-sided, but I thought I might need more room for notes)

The 9VAC wall wart will arrive in the next day or two, but so will the new puppy, and I hope you understand that new pups come ahead of hobbies.

My ADD prevents me from reading the manual from front to back, so I have to look at the TOC and pick a topic of interest to learn a chunk at a time. I did notice this scope can replace my VOM for very precise voltage measurements, and it also has a built-in logic analyzer to replace my old cheap analyzer. (for I2C, SPI, etc)

That is it for now.

First computer 1959. Retired from my own computer company 2004.
Hardware - Expert in 1401, and 360, fairly knowledge in PC plus numerous MPU's and MCU's
Major Languages - Machine language, 360 Macro Assembler, Intel Assembler, PL/I and PL1, Pascal, Basic, C plus numerous job control and scripting languages.
Sure you can learn to be a programmer, it will take the same amount of time for me to learn to be a Doctor.


   
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Inst-Tech
(@inst-tech)
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@zander Looks like your on your way.. The idea of taking it a chunk at a time is a good one..

It won't seem so intimidating after you get a few hours of practice under your belt, and you'll find it a very useful and versatile tool for trouble-shooting.. Let us know how your getting on, be safe, and have fun...BTW, your right, The puppies do come first !.. 😊 😊 

LouisR


   
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Ron
 Ron
(@zander)
Father of a miniature Wookie
Joined: 3 years ago
Posts: 6856
Topic starter  

I did the exercises for the board more or less; they are oriented to the portable scope made by the same company that makes the tutor board. It was not very useful as my scope is different. HOWEVER, at each probe point, I just pressed the AUTO button and the scope configured itself and displayed the signal. I am sure the AUTO button will not work at some point, and I will need to set some settings myself, but for now, I am happy if AUTO works. I plan on doing some basic transistor and OP-amp circuits to use the two channels to display various voltages.

I was hoping to make this a better tutorial, but between a new puppy, ongoing health issues, and my inability to concentrate enough to discover more resource material, this will be going very slowly.

First computer 1959. Retired from my own computer company 2004.
Hardware - Expert in 1401, and 360, fairly knowledge in PC plus numerous MPU's and MCU's
Major Languages - Machine language, 360 Macro Assembler, Intel Assembler, PL/I and PL1, Pascal, Basic, C plus numerous job control and scripting languages.
Sure you can learn to be a programmer, it will take the same amount of time for me to learn to be a Doctor.


   
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(@davee)
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Joined: 3 years ago
Posts: 1641
 

Hi Ron @zander,

Re: your scope tutorial

   Obviously there will be some cases when the 'auto' button will not really help, but most commonly, I would use it as a starting point to get something on the screen, but then use the manual controls to focus on the points of interest, measure time and voltage values, etc.

Obviously, if the waveforms are simple sine/square/triangular waves, then the scope will probably show these values automatically, but in most real situations, such as the inputs and outputs of GPIO pins on a microcontroller, it is more of an eyeball job, albeit you can use cursors, etc. to make it easier.

Best wishes and hope your health is holding up, Dave


   
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Ron
 Ron
(@zander)
Father of a miniature Wookie
Joined: 3 years ago
Posts: 6856
Topic starter  

@davee Understood Dave. If/when my health returns, I plan on building a few circuits utilizing BJT and FET as part of my education. I also want to look into OPAMPs, primarily how they are utilized in Linear power supplies. Those little experiments will give me a more useful way of learning my scope. In addition, I also have the garden monitors and LORA radios that will be useful test rigs for the scope. I also hope to get back to my game cameras, but that may not happen next year unless my health returns to 'normal' very soon.

If you or anyone else can point me to a resource for learning how to use a modern scope that would be helpful.

 

 

First computer 1959. Retired from my own computer company 2004.
Hardware - Expert in 1401, and 360, fairly knowledge in PC plus numerous MPU's and MCU's
Major Languages - Machine language, 360 Macro Assembler, Intel Assembler, PL/I and PL1, Pascal, Basic, C plus numerous job control and scripting languages.
Sure you can learn to be a programmer, it will take the same amount of time for me to learn to be a Doctor.


   
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Inst-Tech
(@inst-tech)
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Posts: 554
 

Posted by: @zander

@inst-tech Thank you, Louis. I hope somebody finds a way to 'fix' YouTube. This video you sent takes 4 minutes to get through the ads, then the display freezes and sometimes starts over if I refresh, and sometimes I get to see the video. I find it ironic that a company that allows so much violation of copyright (AFAIK, it's over 90%) then tries to force its audience to pay to watch the truly free content. I understand some ads are needed to support the platform, but what they are doing now is outrageous.

I am aware of the electronics-tutorials website, but unfortunately, since it is one of those .ws sites today, I can't open the page. I do have it bookmarked and have been able to open the site on other days, but not today so far. It will pass, and I can open it with another browser but that is not ideal.

Perhaps I misunderstood, but I don't see any scope related content on the web site, just opamp theory.

@zander (Ron)... yes, they are two separate contents..the video is for the Oscilloscope, and the other is just opAmp theory... This is what I though you wanted to to know as you stated you were going to use the oscilloscope to learn more about opAmps..

I'm sorry that your having trouble with your YT connections.. but then nothing these days works like it suppose to all the time..lol

Stay well my friend..and have fun!

regards,

LouisR

 

 

 

LouisR


   
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Inq
 Inq
(@inq)
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Joined: 2 years ago
Posts: 1900
 

@zander,

I hope asking questions about scope usage in your thread is OK.  If you can't answer them, I'm hoping someone else subscribed might offer advice.  I've been fence jumping about getting a "scope".  The number of times in the past I would have turned it on don't bode well for the purchase.  The number of times I've broken out the $12 Logic Analyzer and used it, doesn't reinforce the purchase of a >> $100 tool gathering dust.  $12 can collect dust just fine.

At the moment, one of my current projects is to measure power usage and identify when and where spikes and or relatively constant areas start and stop - from... external conditions, or software code regions... devices firing up, steadying, being disabled.  I think I understand oscilloscopes track varying voltage.  What kind of device or add-ons to a scope would I need to watch varying current or power and do things like integrating the area under the curve?  -- Battery life calculations and optimizing timing of events to keep under current limitations or to extend battery life.

VBR,

Inq

BTW - Santa is bringing me a <$100 Vector Network Analyzer for Christmas so that may be the tool quota for a while.  

3 lines of code = InqPortal = Complete IoT, App, Web Server w/ GUI Admin Client, WiFi Manager, Drag & Drop File Manager, OTA, Performance Metrics, Web Socket Comms, Easy App API, All running on ESP8266...
Even usable on ESP-01S - Quickest Start Guide


   
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Ron
 Ron
(@zander)
Father of a miniature Wookie
Joined: 3 years ago
Posts: 6856
Topic starter  

@inq Based on Bill's recommendation I got the Rigol DHO802. I have not used it enough yet to tell you one way or the other if it will do what you want but my gut feel is it will.

I will tag Bill @dronebot-workshop to get his opinion, he has much more time in the saddle than me.

BTW, the big killer re power is WiFi and BT.

First computer 1959. Retired from my own computer company 2004.
Hardware - Expert in 1401, and 360, fairly knowledge in PC plus numerous MPU's and MCU's
Major Languages - Machine language, 360 Macro Assembler, Intel Assembler, PL/I and PL1, Pascal, Basic, C plus numerous job control and scripting languages.
Sure you can learn to be a programmer, it will take the same amount of time for me to learn to be a Doctor.


   
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Ron
 Ron
(@zander)
Father of a miniature Wookie
Joined: 3 years ago
Posts: 6856
Topic starter  

@inq I forgot, I believe my scope decodes most/all the bus signals and displays them in fancy labels etc. So it's a super logic analyzer as well.

First computer 1959. Retired from my own computer company 2004.
Hardware - Expert in 1401, and 360, fairly knowledge in PC plus numerous MPU's and MCU's
Major Languages - Machine language, 360 Macro Assembler, Intel Assembler, PL/I and PL1, Pascal, Basic, C plus numerous job control and scripting languages.
Sure you can learn to be a programmer, it will take the same amount of time for me to learn to be a Doctor.


   
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(@davee)
Member
Joined: 3 years ago
Posts: 1641
 

Hi @inq,

   Apologies for throwing my 2 pence worth into your questions to Ron.

'Normal' scope probes are voltage measurement. Some Hall Effect probes can work as current measurement scope probes, though it is more than a couple of decades since I last saw one in action, and I don't know what is available now.

Alternately, if you can place a resistor in series with the current flow, then in principle you can measure the voltage drop, and use I=V/R to figure out the current. Beware, scope probes measure with respect to 'ground'. Depending on where in the circuit, etc. measuring across a resistor can be tricky.  Differential probes can be used, but I don't know if there are any commercial products in a 'reasonable' price range. Explaining it all is a sermon or three in its own right … I'll leave it for now, but if you have a specific case, we can discuss that.

Scopes are designed for measuring 'relatively' quick changing voltages ... maximum time would generally be a few seconds. This obviously matches in spikes etc., but not monitoring over a longer time period.

For batteries, it is common to look over the time it takes to discharge the battery ... say minutes to years. There are probably commercial solutions, but in the (fairly distant) past I have seen home brew solutions based on some fairly basic analogue circuits (op-amps, etc.), A/D converters and a small computer performing the data acquisition and integration.

It mainly depends on what data you are trying to acquire.

Best wishes,

Dave


   
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Inq
 Inq
(@inq)
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Posts: 1900
 

Posted by: @davee

Hi @inq,

'Normal' scope probes are voltage measurement. Some Hall Effect probes can work as current measurement scope probes, though it is more than a couple of decades since I last saw one in action, and I don't know what is available now.

Alternately, if you can place a resistor in series with the current flow...

Dave

Obviously (since you've been a part of it) I've been playing around with LoRa, antennas, deep sleep and ESP8266's in hopes of coming up with battery operated sensor nodes (of all different kinds).  I'm still at a novice level when it comes to hardware and anything beyond digital "happenings" that I can read with the logic analyzer. 

This realm of of the oscilloscope of GHz, voltage, resistance, impedance, phase shifts is interesting, but I hope only really applies to antenna design (that I need).  I've done some experiments with various antennas and the fact I'm using cook-books leaves an unknown taste in my mouth.  Some show improvements, others not.  I've gone through many of Andreas S piess' YT on antennas and LoRa.  This one

finally convinced me, that the cook-books only get me relatively close and other things are influencing the design.  And when it came down to an >$300 oscilloscope or a <$100 Vector Network Analyzer, I went with the VNA from Santa.  😊 

Back to your comment - Since my only "use" for a scope is currently power usage... and that I'd need other parts to still determine this, I think the scope is for a future need.

Thanks,

Inq

 

3 lines of code = InqPortal = Complete IoT, App, Web Server w/ GUI Admin Client, WiFi Manager, Drag & Drop File Manager, OTA, Performance Metrics, Web Socket Comms, Easy App API, All running on ESP8266...
Even usable on ESP-01S - Quickest Start Guide


   
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(@davee)
Member
Joined: 3 years ago
Posts: 1641
 

Hi @inq,

   Hope Santa fulfils your expectations. I confess I have never played with a VNA, but it should be helpful if you are trying to design the best aerial and feeder. I watched a few of Andreas's videos, including those about VNAs a few weeks ago. I'll be interested to hear how you get on.

Scopes in a 'reasonable' price range, i.e. a few hundred dollars are limited to about 100-200MHz bandwidth, which means they can't see radio frequency signals for things like LoRa at around 900MHz or WiFi at 2.4 GHz and above. They would also struggle with the highest frequencies in microprocessor/controller systems, but can manage much of the I/O traffic, etc., as well as most common analogue circuits.

They are very different tools for different problems.

Best wishes, Dave


   
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Ron
 Ron
(@zander)
Father of a miniature Wookie
Joined: 3 years ago
Posts: 6856
Topic starter  

Getting back on track about learning to use a scope.

Between a new puppy, poor health, and too many other rabbit holes I have made no progress. Now that I think I can get started on the new Linear Power Supply I will at least be able to display the waveforms as it goes from pure AC to full wave and on to fairly ripple free DC.

But first I need to get back to my design after being led astray to complete the 'tricks' I need to play to get power on LEDs to light up. Why 'tricks'? because 3.3V is not enough to light the LED and maybe even 5V at least bright enough. I think I had it all worked out when I got sidetracked.

Hopefully more progress soon.

First computer 1959. Retired from my own computer company 2004.
Hardware - Expert in 1401, and 360, fairly knowledge in PC plus numerous MPU's and MCU's
Major Languages - Machine language, 360 Macro Assembler, Intel Assembler, PL/I and PL1, Pascal, Basic, C plus numerous job control and scripting languages.
Sure you can learn to be a programmer, it will take the same amount of time for me to learn to be a Doctor.


   
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Inst-Tech
(@inst-tech)
Member
Joined: 2 years ago
Posts: 554
 

Posted by: @zander

Getting back on track about learning to use a scope.

Between a new puppy, poor health, and too many other rabbit holes I have made no progress. Now that I think I can get started on the new Linear Power Supply I will at least be able to display the waveforms as it goes from pure AC to full wave and on to fairly ripple free DC.

But first I need to get back to my design after being led astray to complete the 'tricks' I need to play to get power on LEDs to light up. Why 'tricks'? because 3.3V is not enough to light the LED and maybe even 5V at least bright enough. I think I had it all worked out when I got sidetracked.

Hopefully more progress soon.

@zander,  Ron, 3.3v can be sufficient to light up an LED, depending on the forward voltage (Vf) of that LED.. most generic 5mm or 3mm LED have Vf of between 1.8-4 V, depending on color, and semiconducting materials used. I did a test on some of the generics ones I had on had, 5mm, red, gree, yellow, blue, and clear..The following are the result:

image

 As you can see, even at 3.3V, most of the LED's can produce a relative brightness with bewteen 8-9 mA, except the Green and clear, although some of the green ones had a lot lower end range of 2.2 Vf..Most DVM have a diode test function on them, but may not be able to test the LED's that have higher Vf, like the Green, Blue and clear ones.. so a little test rig with a 150 ohm resistor, and you and test them to see how bright they are.. of course, if you what more current to increase the brightness, just reduce the resistance using the formula given in the work sheet.

I think you will solve your problem with the power  on LED with this knowledge..

Have fun, and stay safe!

regards,

LouisR

 

LouisR


   
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