Author Topic: With a budget of $400 - Rigol or Siglent scope?  (Read 17336 times)

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Online rsjsouza

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Re: With a budget of $400 - Rigol or Siglent scope?
« Reply #50 on: January 29, 2018, 02:50:28 am »
Get a scope that has dedicated controls above the inputs, be it a 2 channel or 4

The last thing you need with students hovering about  >:D >:D >:D  is switched/  shared channels BS on a DSO you have to master asap  |O :-// :horse:
IMO I don't see this as a blocking issue. Sure, this can be an annoyance but far from the modern reality - especially when dealing with the fact compact multichannel units are what the students will most probably use after high school is over.

If anything, this will give them a taste of reality... :)

Souds like you might not be aware of what’s going on in our educational system.   Remember “no child get’s left behind”, that also means “no child gets ahead” either.
I understand the issues from the news but, since I did not go to school here in the US, to me an oscilloscope (or whatever other technical/trade equipment) is unheard of in a high school class - thus my impression you were part of a more advanced or better funded school district.

Siglent SDS 1202x-e best price for today. Or 1204- 4 ch. On this day is the best osc. for they price. Not Rigol or somethings else. Rigol is near of the end of life today. lt's obvious. Siglent is fresh decigion. If new products released from Rigol tomorrow - we wll see. But today - Siglent - best scopes today for the price.

As far as I can tell, it doesn't seem like he can get a 4-ch Siglent scope for the $400 budget. With 2 channels, doing meaningful SPI decoding is impossible, so for that reason alone I'd go for a 4-ch model - which seems to only leave the Rigol DS1054z.

Thank you - You are providing the type of assistance I'm looking for.
If your usage was focused in analog signals where the demand for more bandwidth or a better FFT is more important than multiple channels or decode, the Siglent or a Instek would be a better choice.

Appears you didn't see my original post.  Or the post where I explained what I would be teaching.  I am a college professor.  I teach computer networking, virtualization and cyber-security classes.  Our college is trying an outreach program with the high school where high school students are receiving college credit for taking the class.
I did see your area of interest for this oscilloscope. My post was simply a highlight of the main differences of value proposition between Siglent and Rigol.

From your original post it wasn't clear to me where you worked - my impression was that you were a high school teacher. My apologies. 
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Offline imidis

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Re: With a budget of $400 - Rigol or Siglent scope?
« Reply #51 on: January 29, 2018, 03:17:39 am »
I think a scope be it keysight, rigol, siglent even an old analog scope can be a valuable teaching/learning device.  :-+

If money weren't an issue picking one sure would be easier! :)
Gone for good
 
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Offline DougSpindler

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Re: With a budget of $400 - Rigol or Siglent scope?
« Reply #52 on: January 29, 2018, 03:56:11 am »
Get a scope that has dedicated controls above the inputs, be it a 2 channel or 4

The last thing you need with students hovering about  >:D >:D >:D  is switched/  shared channels BS on a DSO you have to master asap  |O :-// :horse:
IMO I don't see this as a blocking issue. Sure, this can be an annoyance but far from the modern reality - especially when dealing with the fact compact multichannel units are what the students will most probably use after high school is over.

If anything, this will give them a taste of reality... :)

Souds like you might not be aware of what’s going on in our educational system.   Remember “no child get’s left behind”, that also means “no child gets ahead” either.
I understand the issues from the news but, since I did not go to school here in the US, to me an oscilloscope (or whatever other technical/trade equipment) is unheard of in a high school class - thus my impression you were part of a more advanced or better funded school district.

Siglent SDS 1202x-e best price for today. Or 1204- 4 ch. On this day is the best osc. for they price. Not Rigol or somethings else. Rigol is near of the end of life today. lt's obvious. Siglent is fresh decigion. If new products released from Rigol tomorrow - we wll see. But today - Siglent - best scopes today for the price.

As far as I can tell, it doesn't seem like he can get a 4-ch Siglent scope for the $400 budget. With 2 channels, doing meaningful SPI decoding is impossible, so for that reason alone I'd go for a 4-ch model - which seems to only leave the Rigol DS1054z.

Thank you - You are providing the type of assistance I'm looking for.
If your usage was focused in analog signals where the demand for more bandwidth or a better FFT is more important than multiple channels or decode, the Siglent or a Instek would be a better choice.

Appears you didn't see my original post.  Or the post where I explained what I would be teaching.  I am a college professor.  I teach computer networking, virtualization and cyber-security classes.  Our college is trying an outreach program with the high school where high school students are receiving college credit for taking the class.
I did see your area of interest for this oscilloscope. My post was simply a highlight of the main differences of value proposition between Siglent and Rigol.

From your original post it wasn't clear to me where you worked - my impression was that you were a high school teacher. My apologies.

Maybe I was not clear in my original post.  I'm not qualified to teach high school students, even through I'm a professor teaching at the college where some of these students might attend after high school.  I'm a networking, firewall, cyber security instructor.  When I was in high school we had an electronics teacher and classes.  My teacher was fanatic.  I was probably in the last class he taught vacuum tubes too.  All of my digital electronics is self taught.  But let me say my electronics teacher taught me well.  In computer networking I use a VOM/DMM regularly.  My high school had scopes.  Those famous Heathkit scopes.  Every student had a VOM and a scope.  So I know who to use a scope in analog mode....  This whole digital think is new, but I think I'm getting it because I understand computer networking/Ethernet.  In discussing which scope to buy I'm realizing all of my knowledge about Wireshark and Ethernet apply.  Malformed packets just another way of saying the trigger voltage was not reached.  (Greatly simplified, but good enough.)

I'm hoping I can show students networking issues with the scope such as mutual-inductance/cross-talk and RFI.

With the Arduino my goal is to show students the bits on the scope and have them decode frames on the SPI bus.  I'm hoping I can show "hacking" by connecting a "foreign" Arduino on the SPI bus and injecting bit to mess things up a bit for them. 

IO hope to master just enough scope knowledge so I these students can see how easy it is for cyber criminals to hack into computers to commit computer crimes.

 






 
 

Offline DougSpindler

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Re: With a budget of $400 - Rigol or Siglent scope?
« Reply #53 on: January 29, 2018, 03:58:48 am »
I think a scope be it keysight, rigol, siglent even an old analog scope can be a valuable teaching/learning device.  :-+

If money weren't an issue picking one sure would be easier! :)

You got that right.  We spend so much money on our military and so little on our students.  Maybe one day that will change.  Don't wsa have less wars when people are more educated?
 
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Online Fungus

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Re: With a budget of $400 - Rigol or Siglent scope?
« Reply #54 on: January 29, 2018, 10:18:56 am »
As far as I can tell, it doesn't seem like he can get a 4-ch Siglent scope for the $400 budget. With 2 channels, doing meaningful SPI decoding is impossible, so for that reason alone I'd go for a 4-ch model - which seems to only leave the Rigol DS1054z.

Correct. The cheapest Siglent is $500 and only has 2 channels.

I made it very clear I have a $400 budget.

That never deters our resident Siglent distributors from jumping in.

 

Offline Siglent America

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Re: With a budget of $400 - Rigol or Siglent scope?
« Reply #55 on: January 29, 2018, 03:06:15 pm »

Actually, the Siglent SDS1202X-E (2-channel) sells for $379 but I am guessing that most of our distributors would provide you with an educational discount.
 

Offline rstofer

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Re: With a budget of $400 - Rigol or Siglent scope?
« Reply #56 on: January 29, 2018, 03:18:52 pm »
Don't overlook the possibility of tying in a little robotics.  It is always illuminating to create a servo pulse and vary the width while watching the servo reposition.  The scope trace adds a lot to the demonstration.

PWM for motor speed control is another interesting demonstration.

Maybe a PING))) device (ultrasonic transducer) where you can see the pulse going out and the ping coming back.
https://www.parallax.com/product/28015

A simple 4 bit counter shows up well on a 4 channel scope.


 

Offline CharlieEcho

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Re: With a budget of $400 - Rigol or Siglent scope?
« Reply #57 on: January 29, 2018, 03:35:18 pm »
I think the Rigol is a good choice for classroom use, even if Siglent is the best hobbyist buy currently. The interface and front panel are closer to Keysight/Tek
with more dedicated HW controls (Siglent is more contextual/modal in terms of the panel and the menus, like LeCroy). I think that's good for education, plus if your students choose to get into electronics that's the more typical setup.  Just put a camera on the screen and front panel and mirror it on a PJ or TV.

You and your students might also enjoy messing with PyDSA, for doing signal analysis on an attached PC.

https://github.com/rheslip/PyDSA


I'm hoping I can show students networking issues with the scope such as mutual-inductance/cross-talk and RFI.

I'm a scope noob myself, but is a 100MHz scope going to be able to show much in terms of ethernet crosstalk on UTP? I know CAT5E theoretically tops out at 100MHz but I thought you needed fancier scopes and spectrum analyzers or else special networking specific test gear for that. Maybe because of the way scope BW is rated (response falls off before the nominal upper limit) and the need for full BW and a wider view across multiple channels when testing ethernet cables? Or maybe I'm totally wrong.

Either way, watch lots of W2AEW's vids before you start blasting your scope with RF.

« Last Edit: January 29, 2018, 07:11:59 pm by CharlieEcho »
 

Online Fungus

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Re: With a budget of $400 - Rigol or Siglent scope?
« Reply #58 on: January 29, 2018, 07:27:14 pm »

Actually, the Siglent SDS1202X-E (2-channel) sells for $379

My bad for being unclear. I thought we were discussing 4-channel 'scopes.
 

Online nctnico

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Re: With a budget of $400 - Rigol or Siglent scope?
« Reply #59 on: January 29, 2018, 08:05:33 pm »

Actually, the Siglent SDS1202X-E (2-channel) sells for $379
My bad for being unclear. I thought we were discussing 4-channel 'scopes.
If you factor in the educational discount the Keysight DSOX1000 (2 analog + 1 digital channels) should also fit inside a $400 budget but I'm not sure whether that includes protocol decoding and the waveform generator options (I guess not).
There are small lies, big lies and then there is what is on the screen of your oscilloscope.
 

Offline DougSpindler

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Re: With a budget of $400 - Rigol or Siglent scope?
« Reply #60 on: January 29, 2018, 11:33:29 pm »
I think the Rigol is a good choice for classroom use, even if Siglent is the best hobbyist buy currently. The interface and front panel are closer to Keysight/Tek
with more dedicated HW controls (Siglent is more contextual/modal in terms of the panel and the menus, like LeCroy). I think that's good for education, plus if your students choose to get into electronics that's the more typical setup.  Just put a camera on the screen and front panel and mirror it on a PJ or TV.

You and your students might also enjoy messing with PyDSA, for doing signal analysis on an attached PC.

https://github.com/rheslip/PyDSA


I'm hoping I can show students networking issues with the scope such as mutual-inductance/cross-talk and RFI.

I'm a scope noob myself, but is a 100MHz scope going to be able to show much in terms of ethernet crosstalk on UTP? I know CAT5E theoretically tops out at 100MHz but I thought you needed fancier scopes and spectrum analyzers or else special networking specific test gear for that. Maybe because of the way scope BW is rated (response falls off before the nominal upper limit) and the need for full BW and a wider view across multiple channels when testing ethernet cables? Or maybe I'm totally wrong.

Either way, watch lots of W2AEW's vids before you start blasting your scope with RF.

Not sure if I can do it, but going to try.  To demonstrate crosstalk I don't beed Gig or 100 Meg, 10 is still supported os I thought i would try that.


« Last Edit: January 29, 2018, 11:50:58 pm by DougSpindler »
 

Offline CharlieEcho

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Re: With a budget of $400 - Rigol or Siglent scope?
« Reply #61 on: January 30, 2018, 01:36:10 am »
Makes sense. Should be plenty of BW for that.
 

Offline DougSpindler

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Re: With a budget of $400 - Rigol or Siglent scope?
« Reply #62 on: February 03, 2018, 02:17:32 pm »
All Just wanted to let you know I did purchase the Rigol scope.  It arrived today. Can’t wait to give it a try.....  What the first thing I want to take a look at......   Gues it would have to be the sine wave from the mains.  Can’t wait.

And yes I watch Dave’s and and few other videos on how to blow the channel measuring mains. 
 

Online Fungus

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Re: With a budget of $400 - Rigol or Siglent scope?
« Reply #63 on: February 03, 2018, 03:13:42 pm »
All Just wanted to let you know I did purchase the Rigol scope.  It arrived today. Can’t wait to give it a try.....  What the first thing I want to take a look at......   Gues it would have to be the sine wave from the mains.  Can’t wait.

Ummm.... danger of magic smoke escaping!

On the right of the 'scope there's a little metal loop which has a test signal. Me? I'd start with that.

After that I'd connect a wire to the sound output of the PC and generate tones with Audacity, play some music, etc.

Look at Arduino pins if you have one, do PWM with a potentiometer.

The absolute last thing I'd ever do with an oscilloscope is connect it to the mains.

Mains electricity isn't a test signal. Not for multimeters, definitely not for oscilloscopes (which are grounded).
« Last Edit: February 03, 2018, 03:17:53 pm by Fungus »
 

Offline DougSpindler

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Re: With a budget of $400 - Rigol or Siglent scope?
« Reply #64 on: February 03, 2018, 04:51:11 pm »
All Just wanted to let you know I did purchase the Rigol scope.  It arrived today. Can’t wait to give it a try.....  What the first thing I want to take a look at......   Gues it would have to be the sine wave from the mains.  Can’t wait.

Ummm.... danger of magic smoke escaping!

On the right of the 'scope there's a little metal loop which has a test signal. Me? I'd start with that.

After that I'd connect a wire to the sound output of the PC and generate tones with Audacity, play some music, etc.

Look at Arduino pins if you have one, do PWM with a potentiometer.

The absolute last thing I'd ever do with an oscilloscope is connect it to the mains.

Mains electricity isn't a test signal. Not for multimeters, definitely not for oscilloscopes (which are grounded).

I frequently use a DMM or VOM meter to measure or test for AC voltage on the mains and branch circuits.  The DMMs I have are all rated to 600 V.  So what’s th problem in using the mainstream test the. DMM or VOM?

As for why using the mains for testing the scope, simiple answer is because it can be safely done.  In fact, soon of the testing I would like to do includes having a scope attached to the mains to see the data being sent devices such as X-10 or PowerLine/Ethernet over AC mains.

There’s only a danger of smoke if you don’t think through what you are doing.
 
 

Offline abraxa

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Re: With a budget of $400 - Rigol or Siglent scope?
« Reply #65 on: February 03, 2018, 05:29:00 pm »
Can't find pricing or for that matter any information about the product.  It would be irresponsible of my to buy a product with tax payer money for an educational instruction without any information other than you saying it has the best price today.  I'm looking for what would be the best value for the college and students.  Price is only one factor when considering value.

To paraphrase you: "It would be irresponsible of me to [waste money]."

As for why using the mains for testing the scope, simiple answer is because it can be safely done.

You're right, it can be done safely. However, even professionals blow up stuff by accident. Or die.
We're not trying to be mean here or spoil your fun, we're just trying to protect you and your equipment.
Your previous posts have emphasized over and over that you're a software kind of guy. That, and the nature of your questions give off the vibe that you're at beginner level when it comes to matters of EE. That's perfectly fine and there's nothing wrong with that, it just means that dangerous situations should be avoided until you have a firm grasp of what the risks are and how to mitigate them. Given the questions you've asked here and your software background, I (and I assume others, too) are uncertain whether you possess the experience to do this, which is why we keep pushing the issue.

In fact, soon of the testing I would like to do includes having a scope attached to the mains to see the data being sent devices such as X-10 or PowerLine/Ethernet over AC mains.

As a teacher, you're aware that your students will be very eager to continue research at home if a topic really interests them. Even if you know how to handle mains voltage, would you trust a high school student to know this, too? If they see your setup at school and think "oh, this is easy" and do it at home as well and set the house on fire or die, how would you feel?
It's one thing to probe mains at your own home for the sake of curiosity. It's another if you do it as part of a class and inspire students to do the same.
 
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Offline CharlieEcho

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Re: With a budget of $400 - Rigol or Siglent scope?
« Reply #66 on: February 03, 2018, 06:20:47 pm »
I know I shouldn't be encouraging this, but maybe a doorbell transformer would be an acceptable expedient? Outputs 16VAC.  Attach a cord a use a portable GFCI.

I agree it's a bad idea to demonstrate the physical act of probing mains service to impressionable kids.
 

Offline DougSpindler

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Re: With a budget of $400 - Rigol or Siglent scope?
« Reply #67 on: February 03, 2018, 06:35:08 pm »
Can't find pricing or for that matter any information about the product.  It would be irresponsible of my to buy a product with tax payer money for an educational instruction without any information other than you saying it has the best price today.  I'm looking for what would be the best value for the college and students.  Price is only one factor when considering value.

To paraphrase you: "It would be irresponsible of me to [waste money]."

As for why using the mains for testing the scope, simiple answer is because it can be safely done.

You're right, it can be done safely. However, even professionals blow up stuff by accident. Or die.
We're not trying to be mean here or spoil your fun, we're just trying to protect you and your equipment.
Your previous posts have emphasized over and over that you're a software kind of guy. That, and the nature of your questions give off the vibe that you're at beginner level when it comes to matters of EE. That's perfectly fine and there's nothing wrong with that, it just means that dangerous situations should be avoided until you have a firm grasp of what the risks are and how to mitigate them. Given the questions you've asked here and your software background, I (and I assume others, too) are uncertain whether you possess the experience to do this, which is why we keep pushing the issue.

In fact, soon of the testing I would like to do includes having a scope attached to the mains to see the data being sent devices such as X-10 or PowerLine/Ethernet over AC mains.

As a teacher, you're aware that your students will be very eager to continue research at home if a topic really interests them. Even if you know how to handle mains voltage, would you trust a high school student to know this, too? If they see your setup at school and think "oh, this is easy" and do it at home as well and set the house on fire or die, how would you feel?
It's one thing to probe mains at your own home for the sake of curiosity. It's another if you do it as part of a class and inspire students to do the same.

Thank you for looking out for me and my students.  I learned how to use a scope in high school as vacuum tubes were being replaced by IC.    The one think in Dave’s video about scopes being attached to the mains (which I don’t think he emphasized enenoug) was the clip and outer ring of the BNC is at Earth ground potential.  So anywhere the clip is attached brining that Earth ground potential to the part of the circuit the clip is attached to.  Or at least this is how I was taught to look at it.

As for how dangerous 120vAC electricity is in the classroom I was trying to find how many deaths there are from non-court ordered electrocutions.   The category is mixed one and includes exposure and radiation so I can get a clear number.

Hear me out for a moment.  I am not saying electricity doesn’t kill.  In our country tht’s one way we carry our cour ordered death sentences.  (And most of the time it is effective, but not always on the first spark).  And let’s not include industrial accidents or people drying their hair with a hair dryer while talking a bath or a shower. 

So how dangerous is 120 vac in an electronics classroom?  I’m going to ask if it could be a good teaching tool?  Have you ever heard of a studnet in an electronics class getting killed?  I know about every year in the US we hear of a high school althelte dying from a high school sports injury.  I have never heard of a high school students being killed from electricity.

When I was in high school I can remembered getting zapped a couple of time creating a arc with a screwdriver/test probe.  Did it kill me?  (Not yet).  Did it ruin some equipment.  Sort of.  The diagonal cutter I was using once now became excellent wire strippers. (+1). And remember this was all before GFCIs.

Guess what I trying to say coming in to close contact with mains can be an excellent learning experience for studnets.  But will it kill them?  Cause a spinal injury or broken bones.  I think the worst thin that could happen is the might get a slight burn.

I’m trying to teach these kids.  And getting a zap of electric, static or mains is all a part of their learning experience.   Can you give me a good reason whey they should get accidentally zapped every once in a while?  You know there’s an arcade not too far from where I have where kids pay to get zapped.  And yet they could come to my class and get it for free?

Look I’m not saying I don’t implement any safety measures, I do.  When students are working with mains I have make sure they are using a GFCI.  And I teach them to test the GFCI before the excercise we are doing.  So should a studnet attach alligator clips to another studnets chair the GFCI would trip before the kid would be smoking.

You know the other stupid thing we did in high shool was charge a capacitor to 150 volts a either leave it on a counter for someone to pick up or toss it to someone to catch.  As a high school kid that was a lot of fun todo, but as an adult I have to say boy was sure stupid of us.  But you know something....  We learned.  We learn never to catch a capacitor toseed to you.  But getting serious for a monent what I taught me was to treat ever capacitor and every circuit even if no power is applied as if it were energized until proven other wise.  It taught me to short/bleed all capacitors before touching. And isn’t that the lesson we want studnets to know?

And as a side note this is interesting.  There are people who have a medical condition which allows them to touch mains without feeling any electricity.  It’s rare, but not unheard of.  So you know if one of these kids doesn’t get zapped when he should it would inform them that they have this rare medical condition.
 

 

Offline DougSpindler

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Re: With a budget of $400 - Rigol or Siglent scope?
« Reply #68 on: February 03, 2018, 06:58:15 pm »
I know I shouldn't be encouraging this, but maybe a doorbell transformer would be an acceptable expedient? Outputs 16VAC.  Attach a cord a use a portable GFCI.

I agree it's a bad idea to demonstrate the physical act of probing mains service to impressionable kids.

Excellent idea.  I already use GFCIs.  And you know I have a door bell transformer - That would be perfect.   I was thinking of a vacuum tube filament transformer.  Hard to find nowadays.  But yes a door heell would be perfect.  Teacches isolations and step down.  I have one on my junk box.  And if not I’ll take the one out of my atttack.  We disconnected our door bell years ago.
   
 

Offline phil from seattle

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Re: With a budget of $400 - Rigol or Siglent scope?
« Reply #69 on: February 03, 2018, 07:17:43 pm »
I’m trying to teach these kids.  And getting a zap of electric, static or mains is all a part of their learning experience.   Can you give me a good reason whey they should get accidentally zapped every once in a while?  You know there’s an arcade not too far from where I have where kids pay to get zapped.  And yet they could come to my class and get it for free?
While I think understanding the dangers is a very good thing, I suggest that "zapping" them will be misconstrued by parents, administrators, police and prosecutors. No matter how you construct the experiment, they won't understand.  Don't do it. Imagine the average parent hearing "the teacher shocked me with electricity today!!". No amount of explanation will overcome their initial reaction. The above mentioned groups freak out over lesser stuff.  You are setting yourself up for a world of hurt.
 

Online Fungus

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Re: With a budget of $400 - Rigol or Siglent scope?
« Reply #70 on: February 03, 2018, 09:18:09 pm »
The one think in Dave’s video about scopes being attached to the mains (which I don’t think he emphasized enenoug) was the clip and outer ring of the BNC is at Earth ground potential.  So anywhere the clip is attached brining that Earth ground potential to the part of the circuit the clip is attached to.  Or at least this is how I was taught to look at it.

That's true.

But... are you going to garantee that every single plug/socket your students come into contact with has been correctly wired and that the colors of the wires will let them know which is the "safe" one?

Have you ever heard of a studnet in an electronics class getting killed?

No, but I haven't heard of a teacher who encourages getting "zapped" either. Will you be so smug when one of them gets hurt?

If you knew a quarter as much as you think you do, you'd also know that getting "zapped" should never happen because you always wear work gloves when you're messing with live mains.

They shouldn't be going near mains AC if you're not teaching them to be electricians, let alone clipping oscilloscope probes onto bare wires. Want to see a sine wave? Get a signal generator, FFS. Or an audio lead. Sheesh.

 
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Offline Someone

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Re: With a budget of $400 - Rigol or Siglent scope?
« Reply #71 on: February 03, 2018, 10:21:57 pm »
All Just wanted to let you know I did purchase the Rigol scope.  It arrived today. Can’t wait to give it a try.....  What the first thing I want to take a look at......   Gues it would have to be the sine wave from the mains.  Can’t wait.
Ummm.... danger of magic smoke escaping!

On the right of the 'scope there's a little metal loop which has a test signal. Me? I'd start with that.

After that I'd connect a wire to the sound output of the PC and generate tones with Audacity, play some music, etc.

Look at Arduino pins if you have one, do PWM with a potentiometer.

The absolute last thing I'd ever do with an oscilloscope is connect it to the mains.

Mains electricity isn't a test signal. Not for multimeters, definitely not for oscilloscopes (which are grounded).
I frequently use a DMM or VOM meter to measure or test for AC voltage on the mains and branch circuits.  The DMMs I have are all rated to 600 V.  So what’s th problem in using the mainstream test the. DMM or VOM?

As for why using the mains for testing the scope, simiple answer is because it can be safely done.  In fact, soon of the testing I would like to do includes having a scope attached to the mains to see the data being sent devices such as X-10 or PowerLine/Ethernet over AC mains.

There’s only a danger of smoke if you don’t think through what you are doing.
The manufacturer of that specific scope strongly advises against using it to make measurements of the mains:
Quote from: RIGOL User's Guide DS1000Z Series Digital Oscilloscope
DS1000Z series digital oscilloscopes can make measurements in Measurement Category I.
WARNING
This oscilloscope can only be used for measurements within its specified measurement categories.
If its not designed to withstand possible transients/faults/events on the mains and tested to safely contain them then don't even think about using it for that in public setting. Mains has an enormous fault energy and while you're thinking of a slight electric shock here and there those of us with more experience are thinking about arcs and equipment exploding with globs of molten material flying out.

If you want to measure mains, you just bought the wrong scope.
 
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Offline tautech

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Re: With a budget of $400 - Rigol or Siglent scope?
« Reply #72 on: February 03, 2018, 10:52:53 pm »

Thank you for looking out for me and my students.  I learned how to use a scope in high school as vacuum tubes were being replaced by IC.    The one think in Dave’s video about scopes being attached to the mains (which I don’t think he emphasized enenoug) was the clip and outer ring of the BNC is at Earth ground potential.  So anywhere the clip is attached brining that Earth ground potential to the part of the circuit the clip is attached to.  Or at least this is how I was taught to look at it.

As for how dangerous 120vAC electricity is in the classroom I was trying to find how many deaths there are from non-court ordered electrocutions.   The category is mixed one and includes exposure and radiation so I can get a clear number.

Hear me out for a moment.  I am not saying electricity doesn’t kill.  In our country tht’s one way we carry our cour ordered death sentences.  (And most of the time it is effective, but not always on the first spark).  And let’s not include industrial accidents or people drying their hair with a hair dryer while talking a bath or a shower. 

So how dangerous is 120 vac in an electronics classroom?  I’m going to ask if it could be a good teaching tool?  Have you ever heard of a studnet in an electronics class getting killed?  I know about every year in the US we hear of a high school althelte dying from a high school sports injury.  I have never heard of a high school students being killed from electricity.

When I was in high school I can remembered getting zapped a couple of time creating a arc with a screwdriver/test probe.  Did it kill me?  (Not yet).  Did it ruin some equipment.  Sort of.  The diagonal cutter I was using once now became excellent wire strippers. (+1). And remember this was all before GFCIs.

Guess what I trying to say coming in to close contact with mains can be an excellent learning experience for studnets.  But will it kill them?  Cause a spinal injury or broken bones.  I think the worst thin that could happen is the might get a slight burn.

I’m trying to teach these kids.  And getting a zap of electric, static or mains is all a part of their learning experience.   Can you give me a good reason whey they should get accidentally zapped every once in a while?  You know there’s an arcade not too far from where I have where kids pay to get zapped.  And yet they could come to my class and get it for free?

Look I’m not saying I don’t implement any safety measures, I do.  When students are working with mains I have make sure they are using a GFCI.  And I teach them to test the GFCI before the excercise we are doing.  So should a studnet attach alligator clips to another studnets chair the GFCI would trip before the kid would be smoking.

You know the other stupid thing we did in high shool was charge a capacitor to 150 volts a either leave it on a counter for someone to pick up or toss it to someone to catch.  As a high school kid that was a lot of fun todo, but as an adult I have to say boy was sure stupid of us.  But you know something....  We learned.  We learn never to catch a capacitor toseed to you.  But getting serious for a monent what I taught me was to treat ever capacitor and every circuit even if no power is applied as if it were energized until proven other wise.  It taught me to short/bleed all capacitors before touching. And isn’t that the lesson we want studnets to know?

And as a side note this is interesting.  There are people who have a medical condition which allows them to touch mains without feeling any electricity.  It’s rare, but not unheard of.  So you know if one of these kids doesn’t get zapped when he should it would inform them that they have this rare medical condition.
::)
..........  Or the post where I explained what I would be teaching.  I am a college professor.  I teach computer networking, virtualization and cyber-security classes.
When I saw this some days ago, I assumed intelligent.
Now I'm not so sure.  :scared:

Your school is charged with the safe education and protection of students while they're in your care.

Please take this responsibility with the greatest of importance ! ! !
« Last Edit: February 03, 2018, 10:56:05 pm by tautech »
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Online nctnico

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Re: With a budget of $400 - Rigol or Siglent scope?
« Reply #73 on: February 03, 2018, 11:52:45 pm »
So how dangerous is 120 vac in an electronics classroom?  I’m going to ask if it could be a good teaching tool?  Have you ever heard of a studnet in an electronics class getting killed?  I know about every year in the US we hear of a high school althelte dying from a high school sports injury.  I have never heard of a high school students being killed from electricity.
Maybe not inside a classroom. When I was a teenager one of my friends from school died because he electrocuted himself by tinkering with mains at home. You have to take into account how well people can estimate their own mortality before learning them how to do dangerous things.
There are small lies, big lies and then there is what is on the screen of your oscilloscope.
 

Offline Someone

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Re: With a budget of $400 - Rigol or Siglent scope?
« Reply #74 on: February 04, 2018, 12:36:32 am »
..........  Or the post where I explained what I would be teaching.  I am a college professor.  I teach computer networking, virtualization and cyber-security classes.
When I saw this some days ago, I assumed intelligent.
Now I'm not so sure.  :scared:

Your school is charged with the safe education and protection of students while they're in your care.
Note that "professor" is used in very different contexts around the world, in the US (and now some of Australia) its simply a term for academic staff and not the prestigious title as it is used in the rest of the world:
https://en.wikipedia.org/wiki/Professor
The usual disclaimer that expertise in a specific field or specialisation does not necessarily apply to any other (even adjacent field) applies strongly here.

A quick google of "Doug Spindler" associates them with a Diablo Valley College:
https://en.wikipedia.org/wiki/Diablo_Valley_College
But then their name does not appear in the staff listings so its possibly either a part time appointment or they have moved on to another institution.
 


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