I see people using oscilloscopes and I was wondering if I should get one.
What do they do exactly and how would it help me with projects?
What do they do exactly and how would it help me with projects?
The basic purpose of an oscilloscope is to give you a plot of voltage vs. time. Unless the signal is repetitive you will need a 'storage' oscilloscope. If you want to compare two or more signals that occur simultaneously you need a 'multichannel' oscilloscope. If you know what the signal should look like and you can observe (with the oscilloscope) what it actually does look like you can use this to verify that your circuit works properly or to troubleshoot it if it doesn't.
Don
I use oscilloscopes often for analog signals that are, what floresta said, repetitive. You look at input and output, compare amplitude and phase shift. I use much less often for digital signals. Some use logic analyzer but I've never used one. Oscilloscopes are expensive so if you're just starting electronics, don't get it yet.
I find that very seldom do I need to look at analog signals so I seldom need an oscilloscope.
While I've almost bought one several times over the past few decades, I still I don't own one.
But I don't really design analog circuits so my needs may be very different from others.
On the other hand I use a logic analyzer quite often and own a inexpensive
USB based model.
There are several USB based logic analyzers out there for under $200.
(Saleae, USBee, ZeroPlus Logic Cube, to name a few)
With a logic analyzer you can look at several signals at once through time.
Even the low end USB based models have 8 or more inputs.
The difference with a logic analyzer vs a scope is the scope can show the actual voltage
but the logic analyzer will only show you whether the signal is a logic "high" or a logic
"low".
So what is a logic analyzer good for?
Suppose you want to "see" what a PWM signal looks like to verify the timing.
You can do this with a logic analyzer. (you can often do this with a scope as well)
Most logic analyzers now even have signal decoding software which allows you
see what the signal transitions "mean" which can save a ton of time when looking at signals.
For example, it can do things like turn the wiggling serial output pin back into ascii character data.
Or analyze the signals in a SPI interface as commands or data, or view the commands/data on
a I2C, CAN, or 1-Wire interface.
I often use a logic analyzer to profile my software to determine how fast/slow my code
is running and identify problem areas.
To do this, you pick one or more i/o pins and them strobe them up and down at
various points on your s/w and then you can use the logic analyzer to show the time
in between the various strobes. It adds very little runtime overhead to the code
and is usually quite easy to drop in.
--- bill
maybe good for a beginner?
For most of the work done by people with uCs these days my vote is for a logic analyser.
An LA is absolutely the most useful tool an embedded developer can own IMO (after a compiler of course:)).
Rob
RobDrizzle:
Digital Oscilloscope DIY Kit - KIT-09484 - SparkFun Electronicsmaybe good for a beginner?
Sounds like the answer to that is no:
http://tronixstuff.wordpress.com/2010/05/07/kit-review-jye-tech-oscilloscope/
Well maybe you start the scope as a beginner.... end finish it as a master! lol...
I might still give this one a shot, Maybe sparkfun put some work into the directions.
I think if you really want a small portable, low end scope low speed scope,
I go with the DSO nano or nano 2 from seeedstudio. Its only about $20-$30
more than the SparkFun scope price (lots of vendors carry it)
and it is a much more finished product with a much better display
and a lot more memory for sample storage.
--- bill
I think if you really want a small portable, low end scope low speed scope,
...have a look at the Rigol range.
i got a rigol 1052e and i love it.
I love my cheap Bell & Howell (Heathkit) oscilloscope. I got it for $35 on craigslist, and it is rated to 5mhz but will go beyond that. It is extraordinarily useful for hardware design. It also allows you to reverse-engineer analog devices much more easily. You can detect switching frequencies of pretty much anything. For example, my flashlight's internal boost converter operates at 800khz (detected with a wire coil). There are really countless uses, and for the price you can get a cheap one for it's very worth it.
One thing that I don't have that I recommend as well (but don't have personally) is a logic analyzer. When reverse engineering, I often wish for one of these things.
Oscilloscopes are for analog, logic analyzers are for digital.
wyager:
Oscilloscopes are for analog, logic analyzers are for digital.
Since all electronics are inherently analog, it should be understood why an oscilloscope is useful for so-called "digital" circuits (hint: in real life, square waves are rarely "square").
There do exist full-waveform sampling logic analyzers - they're effectively multi-channel oscilloscopes, and have the high prices of such to boot (once you go beyond 100 MHz and 4 channels, the prices on o-scopes become unreal).
Another possibility (the cheapest!!!) is to use a software scope. One i use is free and open. http://xoscope.sourceforge.net/
It reads two signals from your audio card and displays on your pc. you have only to sold the probes on the mic-jack.
I'm not an expert, so as far as i know the first problem is that you have to pay attention on what you probe, 'cause high currents will kill your audio card. i have three probes to switch with different resistors on, so i use them from the highest to the lower, depending on what i'm measuring. (but for sure i use this only for logics or pwms.) the second of course is that (afaik) it doesn't give you a real voltage reading.
But after that i find it useful to read if digital signals are dirty, if square waves aren't square and if a signal is different from another.
maybe other more expert can tell you more/better.
ciao!
wyager:
I love my cheap Bell & Howell (Heathkit) oscilloscope. I got it for $35 on craigslist, and it is rated to 5mhz but will go beyond that. It is extraordinarily useful for hardware design. It also allows you to reverse-engineer analog devices much more easily. You can detect switching frequencies of pretty much anything. For example, my flashlight's internal boost converter operates at 800khz (detected with a wire coil). There are really countless uses, and for the price you can get a cheap one for it's very worth it.One thing that I don't have that I recommend as well (but don't have personally) is a logic analyzer. When reverse engineering, I often wish for one of these things.
Oscilloscopes are for analog, logic analyzers are for digital.
Here's a basic logic analyzer you can get for $50 shipped worldwide (the wiki page has the old price of $45) Open Bench Logic Sniffer - DP
It's a great little unit for the price.
it has
•70MHz+ sample speeds
•32 channels
•16 buffered, 5volt tolerant channels
•USB interface, USB powered
•USB upgradable everything
Oscilloscopes are for analog
I've been doing it wrong all these years.