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I was asked in an interview the question "why does A x100 oscilloscope probe grant a wider bandwidth than a x10 probe? How much does it widen it?".

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  • \$\begingroup\$ This video covers some relevant things. I'm not certain (and I haven't watched the video), but I think the difference in capacitance causes the change in bandwidth due to a different rise time. \$\endgroup\$ – Greg d'Eon Jan 19 '15 at 1:40
  • \$\begingroup\$ That's a dumb question. I have a x10 probe at the desk in front of me which has twice the bandwidth than a x100 probe, also on my desk next to the first one. Under the desk, I have a x1 probe with the bandwidth wider than other two probes combined - it is active though. \$\endgroup\$ – Oleg Mazurov Jan 19 '15 at 3:03
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I've never used a x100 probe, but I'd guess less capacitance.. same thing from x1 to x10. Bandwidth goes as 1/RC at low frequency, at some point that has to stop.

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  • \$\begingroup\$ Thank you I figured it out.:) BW=0.35/(Risetime) Risetime=2.2(Rin*Cprobe) for x10 probe : Cprobe=15pf for x100 probe : Cprobe=2pf \$\endgroup\$ – dfeast Jan 19 '15 at 3:35
  • \$\begingroup\$ @user4422012, excellent. I measured the (DC) capacitance of a x1 probe the other day it was about 100 pF. Do you know it's perfectly alright to answer your own question? You could add some links to different probes. \$\endgroup\$ – George Herold Jan 19 '15 at 14:10
  • \$\begingroup\$ You probably measured the coax cable capacitance \$\endgroup\$ – Mike Apr 24 '17 at 19:58

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