EEVblog Electronics Community Forum
Electronics => Beginners => Topic started by: Technobabble_ on December 26, 2017, 02:12:59 am
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First Post here!
I recently obtained a BK Precision 2120B oscilloscope, as well as other test equipment. It did not come with probes.
From my reading, oscilloscope probes should:
1. be 10x (for general application), ideally switchable to 1x or 100x
2. Match the input resistance and capacitance, which can be tuned. (1 Mega-ohm and 25 pF in this case)
I know for the probe it must be rated for the input resistance of the oscilloscope; does the input capacitance have to match as well?
I'm considering:
el Cheapo Probes (Amazon, Aliexpress) (https://smile.amazon.com/RioRand-Oscilloscope-Clip-Probes-Accessory/dp/B0030KWM30/ref=sr_1_3?ie=UTF8&qid=1514082367&sr=8-3&keywords=oscilloscope+probe): People seem to have decent results with it.
Pintek (Ebay) (https://www.ebay.com/itm/1pc-Oscilloscope-Probe-Kit-CP-2100-x1-x10-100Mhz-600V-10M-13pF-PINTEK-Taiwan/142102794248?hash=item2115fc9008:g:~fsAAMXQsMZRmFtN): Some forum members recommended these. Taiwan made.
Cal Test (Digikey) (https://www.digikey.com/product-detail/en/cal-test-electronics/GE1501/BKGE1501-ND/6041706): I don't know anything about this one.
Additionally, I want to get BNC mini-grabbers and terminal attachments for the signal generator and function generator.
Will I be OK with cheap Amazon/Aliexpress attachments for the time being?
Is there such a thing as a budget brand BNC connector? What mfg to look for?
Is there a specific brand of connectors you recommend (Pomona, Muller, Cal-Test)?
I've attached the datasheet below.
Thanks.
edit: oscilloscope model no.
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The Amazon ones are perfectly good probes, well within claimed characteristics. They are available under various brands. They come up first if you search eBay for "100mhz oscilloscope probe", sometimes even cheaper than on Amazon.
You are not risking too much there, at $12 you can't beat that price.
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Will I be OK with ebay BNC connectors for the time being? Quite a few people seemed to have issues the the pins not making contact at all when plugged in.
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Will I be OK with ebay BNC connectors for the time being? Quite a few people seemed to have issues the the pins not making contact at all when plugged in.
If you are talking about the probe connector, then it is fine. Or at least I had no problems with them.
If you are talking about separate connectors, then I don't know, it will probably depend on the supplier, but I would not count on them being super high quality.
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Will I be OK with ebay BNC connectors for the time being? Quite a few people seemed to have issues the the pins not making contact at all when plugged in.
Some cheap Chinese test leads you can get off Ebay have BNC connectors that are simply machined poorly. I've posted pics of them in the past. It's a matter of tolerances on one or more of the parts of the connector, and it's hard to tell from the pictures they post on Ebay. Just be aware of this, and take your chances as you will (as I do). :-\
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I know for the probe it must be rated for the input resistance of the oscilloscope; does the input capacitance have to match as well?
For attenuating probes, the compensation capacitance range must encompass the input capacitance of the oscilloscope which is rarely a problem. This only applies to attenuating probes; x1 probes have no compensation.
el Cheapo Probes (Amazon, Aliexpress) (https://smile.amazon.com/RioRand-Oscilloscope-Clip-Probes-Accessory/dp/B0030KWM30/ref=sr_1_3?ie=UTF8&qid=1514082367&sr=8-3&keywords=oscilloscope+probe): People seem to have decent results with it.
I have a bunch of these. My only complaints about them are that the witch's hat grabbers are not very good and the x1/x10 switches fail open after a while.
Even if a x1 probe's bandwidth is sufficient, it is usually better to use a x10 probe for its lower input capacitance unless the extra sensitivity is absolutely required.
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My only complaints about them are that the witch's hat grabbers are not very good and the x1/x10 switches fail open after a while.
I just epoxy the switch in x10 position. Solves that problem forever. I just have a couple probes that have the switch in its original state, but I never use them.
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be 10x (for general application), ideally switchable to 1x or 100x
Keep in mind that switches will eventually fail, and that sooner rather than later the switch will be in the "wrong" position.
If you aren't going to measure low level signals, then *1 isn't necessary. For logic signals, just use a *10.
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Agree with tggzzz/ataradov on the switchable ones being problematic. I’ve got some Wittig 100MHz ones which are quite nice. They’re even nicer with a blob of epoxy on the switch as suggested. Got four probes for my analogue scopes: 3x glued 10x, 1x glued 1x wrapped with red tape. Two 10x probes for channel 1/2, one 10x for trigger and one 1x for low noise measurements (rarely used)
My digital scope retains the four original switchable probes because I want to keep that in good condition because it’s being replaced by a nicer one soon :)
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Do I have to make sure to use electrical tape to keep the 'scope pixies in the probe? :)
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In my case it’s to stop the wally holding the probe from thinking it’s a 10x :)
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https://www.ebay.com/itm/MILITARY-SURPLUS-35-MHZ-10X-OSCILLOSCOPE-PROBE-KIT-HOOK-BANANA-FLEX-ALLIGATOR/201583873667?epid=1769496603&hash=item2eef55ce83:g:W4gAAOSwt7pXNfYx (https://www.ebay.com/itm/MILITARY-SURPLUS-35-MHZ-10X-OSCILLOSCOPE-PROBE-KIT-HOOK-BANANA-FLEX-ALLIGATOR/201583873667?epid=1769496603&hash=item2eef55ce83:g:W4gAAOSwt7pXNfYx)
Has Anybody used Avex probes?
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Has Anybody used Avex probes?
At 35 MHz those Chinese ones will be perfect anyway, so why pay more for something that has worse performance and looks highly uncomfortable too hold. Being military, they probably can sustain direct hit with a bullet, but who cares? Plus with Chinese probes you get two times more for the same price.