Got a crash course in probes when I did my first USB scope design !
Always use 10x or 100x as x1 will produce a fast roll off due to 10pf scope input capacitance.
In x10 and x100 mode the 10pf is offset by caps in the scope probe and so you get better bandwidth.
Always use 10x or 100x as x1 will produce a fast roll off due to 10pf scope input capacitance.
In x10 and x100 mode the 10pf is offset by caps in the scope probe and so you get better bandwidth.
They can be good (or better) at some specific things (as it was described here), but in general it is good to have an individual oscilloscope.
Last edited:
I have examples of both USB scopes (200 MHz) dedicated digital scopes (Siglent and Tek) and analog scopes. The first figure of merit is the analog bandwidth. If the analog circuit rolls off more samples won't help. Second, you should have at least 5X sample rate over the bandwidth limit or you will get into a lot of ugly aliasing and other misleading stuff. Digital scopes can be really misleading if you don't understand how they work. Buffer size is an issue. Too small and you will miss stuff. Too big and it takes a long time to load and show the waveform. What you see is never instantaneous like an analog scope.
All digital scopes are very much a product of the software and some of the cheap ones have pretty limited software. I like the Picoscope software and its continuous improvement (for no cost). However their USB scopes are more expensive.
However a cheap tool that is not useful is actually far more expensive than an expensive tool you use. (I have a collection of those useless cheap tools. . .)
Do not get distracted by features you will never use (serial decoding, mediocre FFT etc.) and don't pay for them if you can avoid it.
For occasional use a USB scope can be quite adequate and stores in a small place. A digital scope will be larger but self contained and analog scopes will be large to really large and power hungry. My old TEk 547 used 500W. The 7854 uses 150W. The Siglent maybe 20W and the Picoscope runs on USB power (2.5W). (However the sampling plugins on the 7854 get me to 20 GHz which would be crazy expensive any other way so its still using a lot of floor space.)
All digital scopes are very much a product of the software and some of the cheap ones have pretty limited software. I like the Picoscope software and its continuous improvement (for no cost). However their USB scopes are more expensive.
However a cheap tool that is not useful is actually far more expensive than an expensive tool you use. (I have a collection of those useless cheap tools. . .)
Do not get distracted by features you will never use (serial decoding, mediocre FFT etc.) and don't pay for them if you can avoid it.
For occasional use a USB scope can be quite adequate and stores in a small place. A digital scope will be larger but self contained and analog scopes will be large to really large and power hungry. My old TEk 547 used 500W. The 7854 uses 150W. The Siglent maybe 20W and the Picoscope runs on USB power (2.5W). (However the sampling plugins on the 7854 get me to 20 GHz which would be crazy expensive any other way so its still using a lot of floor space.)
Well said Jack. A large number of the customer complaints on regulator noise I used to see were really due to improper probing.
PS I noticed your location, first I didn't think that village was in NJ, second are you the only DIYer in the village?
