Replace Tektronix 2215A with USB scope?

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#1
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Hi All,

I picked up a Tektronix 2215A last year for $100 off of Craigslist. I am just starting to need to use it.

The scope is bit larger than I'd like with my current setup, and I'm debating selling/donating it and picking up one of the sub $200 USB scopes.

I think something like the DSO Nano or a USB scope would suit me fine for quite a while. Any good reason why I should reconsider?

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I would not (!) give away the TEK scope. Better get an
USB scope additionally and then decide. But only
get an USB scope that really has added value for you.

http://www.seeedstudio.com/depot...

This one has only 1MHz. That's not enough for microcontroller hardware debugging.

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You really need 100 MHz bandwidth, I'd stick with the 2215A. I still use my 100 MHz 2235.

Leon Heller G1HSM

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Hmm, well maybe I am better off keeping it. Its has 1 set of probes, however I don't know if they are 1x, 10x, etc.
Is there a simple way to test these to see if they are still good, or should I just buy a new set?

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I recommend that you get a manual for the scope.
I think you can download it from Tektronix. The
scope has an internal Signalgenerator to calibrate
probes. See how that works out with your probes.

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Do NOT buy a USB scope - speaking from experience they are (or at least the PoScope is) complete rubbish. They have very limited bandwidth and perform badly if your USB bus is unable to accommodate the amount of data being sent to it. Either keep the scope you have or if you can pony up the $360 minus what you get for selling it and buy one of these: http://www.dealextreme.com/details.dx/sku.30573.

- Dean :twisted:

Make Atmel Studio better with my free extensions. Open source and feedback welcome!

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badpacket wrote:
I don't know if they are 1x, 10x, etc.
Is there a simple way to test these to see if they are still good, or should I just buy a new set?
Attenuation is set by series resistance. 10x probe is 9M-ohm ('scope input should be 1M-ohm). You should be able to set capacitance at the tip or the SMA end of the probe, using a plastic screwdriver (usually come with probes - your local shop or someone with a few sets of probes would probably give them away).

'system frequency' = 1/(1/'scope freq.' + 1/('probe freq.'))
eg., with 100MHz probes, you the max freq. signals you should rely on measuring is 1/(1/60MHz + 1/100MHz) = 37.5MHz or ~9.3ns rise time. For square wave, this puts the limit at ~10x less than that, at 4MHz. (Though you'll see higher, they will be distorted.)
I just went through this...

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A 10x probe terminated into 1Mohm scope input does not necessarily have 10Mohm input impedance, I have one with 2.2Mohm input impedance right here.

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OK, thanks everyone I'm going to keep it.
If I use this enough, I'll spring for the Rigol.

The probes I've got have no adjustments, nor markings except they say Japan on the spring loaded clamps.
Found the manual, and the 500hz signal generator and getting a nice square wave for what thats worth.

Appreciate the advice.

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Because it has no adjustment screws, I fear they may be 1x probes that usually have quite a bit less bandwidth than your scope.

You could use a multimeter to find out what kind of probe you have.

If probe tip is directly connected to BNC middle pin, then it is a 1x probe. If something else, take resistance measurements from tip to BNC middle pin, tip to BNC ground ring, and BNC middle pin to BNC ground ring, and you have a schematic of the probe resistances. My probe measures 2000K/2288K/288K, which means when scope impedance 1M is in parallel with the 288K resistance, the probe has 10x attennuation and input impedance of 2.2Mohms.

If they are 1x probes, I highly suggest getting 10x probes, because they have better bandwidth and impose less resistive and capacitive load on measured circuit than 1x probes. 1x probes may be necessary for very small amplitude signals though.