My First Oscillioscope

Hi-

I am currently looking into getting my first oscilloscope. I am 16, and junior in high school and I work on a range of different electronics projects.

I come with two questions. The first is too vague I know but its a starting point: What scope should I get?

I have so far been looking at 3 scopes, all in approximately the same range. They are all Siglent.

http://www.amazon.com/Siglent-SDS1072CML-TFT-LCD-Bench-Top-Oscilloscope/dp/B00GQNNHJG/ref=sr_1_4?s=industrial&ie=UTF8&qid=1397519149&sr=1-4&keywords=siglent+oscilloscope

I am looking at these because they seem to offer the best product in that price range, and all the reviews I have read have been decent. I am seeking input on this purchase. I do see me going into a college path where one would be useful, so I am unsure to get a good one now, or get an ok one for now, and get a better one later.

My second question is: What is an oscilloscope used for? I know what they do, how they work, and what to use them for, but I am curious as to how a scope fits on your workbench. Do you use it often? What aspects of a project require it? Why does it seem to be such a quintessential tool for working in electronics? I want to know how a scope fits in to your bench and when and how you use it.

Thanks in advance for your input!

-Nick

N314:
My second question is: What is an oscilloscope used for? I know what they do, how they work, and what to use them for, but I am curious as to how a scope fits on your workbench. Do you use it often? What aspects of a project require it? Why does it seem to be such a quintessential tool for working in electronics? I want to know how a scope fits in to your bench and when and how you use it.

Thanks in advance for your input!

-Nick

You use it when you have to watch how the signal changed over time. Like audio signals, or fast control signals. For example, if you measure a short 5v impulse, with a DVM you won't see 5v because it's too fast for it, you will see a few mv. Unless it has a peak function.
It's not as essential as a DVM.
I use it a lot for audio and to measure multiple timing events and see if they're in sync

Look into GW Instek scopes also. Made in Taiwan vs made in China. I have a GDS-2204A, 4 channel, 200 MHz. Wide screen, works great.

If you are doing a lot of digital stuff, then a logic analyzer is a great tool.
I have a Saleae Logic 8 channel analyzer. Samples at 24 MHz, useful for SPI running at Arduino 8 MHz max speeds.

If I had bought the scope first, I may have purchased the analyzer plug in for the scope instead.

My son goes to RPI right now, they are using this for lab work
http://www.digilentinc.com/Products/Detail.cfm?NavPath=2,842,1018&Prod=ANALOG-DISCOVERY&CFID=4552925&CFTOKEN=c91d0c73d10d867b-E058B6FB-5056-0201-02AB08FD77C42858
with Lenovo T430 laptops. Each student has their own of each.

Yes i do actually already have a logic analyser, the salea 8.

I have looked into computer plug in scopes, however without a laptop, and the fact that i would mostly use it on my bench i am leaning more toward a stand alone unit.

-Nick

I used a USB scope for a while as well, I really like having a standalone again. The GW Instek accepts a memory stick to record screen shots, I have posted them here in the forum.

Well one thing I cant decide is between the http://www.amazon.com/Siglent-SDS1052DL-TFT-LCD-Bench-Top-Oscilloscope/dp/B00GQNN70A/ref=lp_393269011_1_15?s=industrial&ie=UTF8&qid=1397409754&sr=1-15
($271)
and the $379 http://www.amazon.com/Siglent-SDS1102CML-TFT-LCD-Bench-Top-Oscilloscope/dp/B00GQNNL1U/ref=sr_1_1?s=industrial&ie=UTF8&qid=1397519149&sr=1-1&keywords=siglent+oscilloscope

an extra $100 gets me twice the bandwidth and 2M long term memory vs something like 40k. Is it worth it? How much would the bandwidth help with general use?

-Nick

A rule of thumb is that the bandwidth needs to be 10x the signals you want to look at.

An Arduino can put out an 8MHz signal so you need 80MHz or more to see that properly.

2M memory vs 40k? Just that alone is worth the extra $100.

As for bandwidth, fungus is right on. Square waves have odd harmonics, the more that get lost, the more it looks like a sine wave. I consider the 9th harmonic the minimum, and the bandwidth is measured where the response is -3dB down, so 10x the square wave frequency is a good rule-of-thumb.