Oscilloscope

[beakie]

Hi all,

I am trying to get an oscilloscope and due to my limited budget have been looking at some cheap pc usb oscopes.

I appreciate these are a probably considered a bit of a toy but I was wondering if they will do for the purpose I have in mind. I need it as a means of debugging serial communications between a pic chip and random serial devices (with a maximum baud rate of 9600).

Here is the one I am looking at...
**broken link removed**

I completely appreciate the needs of most wouldn't be satisfied with this device but do you think it will cater for my job? It seems to but I am probably missing something.

Anyway, a couple of words/thoughts from anyone willing to write em would be massively appreciated.

Thanks

Gary

 

[MikeMl]

The sampling rate is somewhat marginal, even for debugging 9600baud.

 

[antknee]

Its not clear to me exactly what you want to do with the scope. However I bought a brand new oscilloscope from Maplin for £80. I posted to ask about one on this board and a lot of people poo pooed it saying I should get a second hand multi function high spec one from ebay. But I won't buy second hand with all of its associated problems if there is low spec new. I can only say this scope is fantastic. If you are a hobbyist or dont mind low spec then you shouldn't look any further.

**broken link removed**

 

[crutschow]

The device has a sampling rate of 150k samples/s and a maximum frequency response of 50kHz (for an estimated oscilloscope rise time of 7µs), so it may be marginally adequate for your requirements if you are not too concerned about signal fidelity (such as actual rise and fall times).

Note that that fastest sweep rate is 100µs/div which means that that one cycle of a 10kHz signal will occupy one division on the screen. So it doesn't have much time-base resolution for signals above a few kHz.

Also note that to measure greater than 800mV you will need 10:1 probes.

Edit: If you consider another oscilloscope, I would recommend at least a dual channel 'scope.

 

[beakie]

Thanks for both your comments!

MikeMI, I did wonder this myself. I know I am just inside the "frequency range" but understand it is advisable to go much higher. If I were to run multiple tests, couldn't I increase the accuracy of my results by using an average?

Antknee, thanks for the link. I read a few similar posts and (like u, I presume) would spend more if I could, but am working with a limited budget. What sort of baud rates/frequencies do you work with? Anything as high as 9600?

Thanks

Gary

 

[beakie]

If you consider another oscilloscope, I would recommend at least a dual channel 'scope.

Thanks for replying.

Can you recommend one for my needs and around that amount? What about the link sent above?

 

[antknee]

The unit is accurate to around 99%. For example I work at around the 100KHz frequency, it will meausure at 100KHz but the actual frequency may be 99.5KHz - 100.5KHz. If i'm working at higher frequencies up around the maximum, lets say it measures 1.92MHz, the actual frequency may be 1.90 - 1.94MHz. If i measure more wavelengths I can increase the accuracy, I just dont need better than that. It measures up to 200V.

I don't work in baud, so have no idea what that is!

 

[beakie]

Edit: If you consider another oscilloscope, I would recommend at least a dual channel 'scope.

What do you think about this?

**broken link removed**

Am I pushing it?

 

[nigelwright7557]

I bought a £40 scope off ebay with only one channel working.
It seems to work very well and has done for a couple of years now.

On the other hand I bought one from a second hand vendor and what they sent me must have been 20 years old and was sent back 3 times coz it didnt work.
In the end they kept it and gave me my money back.

 

[bychon]

I bought the best one I could afford...in 1977. I'm still using it. Only had to repair it once.
That was the right thing for a "kid" who knew he would be interested in electronics forever.
I don't know if you're between 15 and 25 years old. I don't know if you've realized you are fascinated with electronics, and probably always will be.
If this baud thing is a detour from what your real interest is, don't do what I did.

 

[beakie]

I don't know if you're between 15 and 25 years old. I don't know if you've realized you are fascinated with electronics, and probably always will be.

27 and yes, I would imagine I will be