Cheap PC Oscilloscopes - Any Recommendations?

Missionary Man asks: "I'm an electronics teacher looking for a good (but reasonably cheap) PC based oscilloscope for classroom demonstration purposes. I've done a reasonable amount of research and come up with a few contenders. Ideally I'd like something with a bandwidth of up to 40MHz and 2 channels. Does anyone have any tales to tell regarding the use of any of these scopes (or any others I haven't found or mentioned) and can recommend a suitable device?"

"Here's the list of my findings so far:

• The DS2200C from USB Instruments will do 2 channels at 12 bit resolution, but only to 200KHz.
• The PCS100 from Velleman at QKits runs to 12MHz, but only 1 channel. It has a bigger brother, the PCS500, that has 2 channels and 50MHz bandwidth, but is a lot more expensive.
• Picotech do cheaper ones, like the ADC-40/42, but these only operate in the KHz ranges.
• Link Instruments sell the DSO-2102S that runs to 60MHz with 2 channels, but it's a bit out of my price range.
• Finally, I found the bitscope which seems to be just what I'm looking for, combining a 2 channel scope and an 8 channel logic analyzer for a reasonable price.

I'm hoping to spend US$300-$400. I recognize the software is a fundamental part of the successful operation of these units and any comments regarding the bundled programs would be most helpful too!"

Comments

Educational device

[Rosco P. Coltrane]

Two thoughts about your question:

- Do you really need 40MHz for educational purposes? Unless this is a device to be used in a college or higher education class , you can display sub-10KHz signals to teach a class how to use a scope.

- When I was at school, I learned how to use a real scope, with knobs and buttons and a not-so-perfect green screen, and I reckon it was way better to touch these dials and controls and have a direct feel for what they did on the screen than set some virtual thing and grab perfect-looking samples, to understand how things actually worked.

In short, any old regular scope that's well explained by the teacher is probably better than any interface+software setup that "isolate" the student from whatever electrical phenomenon he's trying to expose.

Re:Educational device

[Rosco P. Coltrane]

On the one hand, it's cool when kids get to learn with the best equipment.

I'm afraid this is one of the greatest misconception in the world education. It's definitely not cool when kids get to learn with the best equipment : kids should learn the basics on simple, self-explanatory equipment. Complication and better equipment can come later, when the basics are understood.

That's the same reason why, after universities have taught CS students Java, C++ and Visual Basic before C and assembler, and churned out unfinished computer "engineers" for years, us low-level programmers still get high-paying jobs doing the old non-object-oriented, boring un-cool engineering the right way.

Please... Don't go the PC route for this...

[KC7GR]

For the amount of money you're specifying, you can easily pick up a much better built and far more versatile O-scope in the form of an older Tektronix instrument.

In fact, that price range will easily get you a 475 or 475A, good to 200 or 250MHz, respectively. It will also put you well within reach of a nice Tektronix 7000 series benchtop 'scope, like a 7704 or even a 7904.

No matter what you may hear, the PC was never designed to be an O-scope, and no amount of external hardware, I believe, will ever turn it into anything that can compare, in terms of value for the $$ and quality of construction, with early Tektronix hardware.

I believe it's also EXTREMELY important to teach would-be technicians and engineers that the PC is not the be-all and end-all of test gear. Never has been, never will be. Oh, it can be useful as an instrument CONTROLLER in automated test setups, yes, but it was never intended to replace the functionality of actual made-for-purpose test equipment.

Give your students a real education. Get a real oscilloscope.