1X or 10X - Page 1
Forum section: electronics / testgear

author: Muggs
author_rank: Newbie
timestamp: December 31, 2020, 06:28:05 pm
content: Hello All,New to Oscilloscopes and to Electronics in general. My questions is, when using a probe there is a 1X/10X switch. However if I use something like a BNC to alligator probe what should I set my scope at? 1X or 10X.This probably seems like a really dumb questions and my suspicion is 1X, but I just thought I would ask.Thanks,Muggs

author: janoc
author_rank: Super Contributor
timestamp: December 31, 2020, 06:32:42 pm
content: The scope setting only affects the scaling of the values on the screen. So you will see 10V on the display instead of 1V if you set it to 10x. This is a convenience in order to compensate for the 10x attenuation of the 10x probe. It has no other effect.So if you are measuring with a piece of coax and banana jacks, you should have it set at 1x so that you don't get 10x higher values on the display (coax doesn't have the 10x voltage divider).

author: Muggs
author_rank: Newbie
timestamp: December 31, 2020, 06:41:57 pm
content: janoc,Thank you! That's what I assumed, so thanks again for confirming. Indeed, if I set the probe to 10x and look at the Vpp, it goes up by 10!Muggs

author: RoGeorge
author_rank: Super Contributor
timestamp: December 31, 2020, 07:08:54 pm
content: With random alligators cable, set the oscilloscope to x1. The dividing x10 probe is only available when proper oscilloscope probes are connected.With oscilloscope's probes, there might be a switch on the handle of the probe that says 1x or 10x. When the probe switch is on 10x, the oscilloscope setting must be on 10x, too, or else it will lie to you regarding the voltage, i.e. saying it sees 100V instead of 10V.When the probe is on 10x, there might be necessary to adjust the trimmer on the probe, so that the testing square wave signal available somewhere on your oscilloscope will look as square as possible. Search for "adjusting probe compensation" for more details.Square wave compensation is only for when the probe switch is set on 10x. When the probe is on 1x, the probe compensation capacitor does nothing.On 10x, the impedance is also 10 times bigger (about 10 Mohm instead of just 1 Mohm) and the bandwith is much bigger on 10x, so it is preferrable to keep your probes on 10x (and the oscilloscope on x10, too) if there is enough voltage.Only when the voltage is very small, you may want to switch your probe to 1x and the scope setting to x1, but that will lower the impedance to only 1 Mohm instead of 10, and will limit the frequency bandwidth, too.As a thumb rule, it's ok to use alligator wires for audio signals or other signals less than 1-10 MHz and with slow rising edge. If the frequencies are higher, or the edges are very fast, even with audio square wave you will need to set the probe switch on 10x.

author: Mr. Scram
author_rank: Super Contributor
timestamp: December 31, 2020, 07:19:05 pm
content: Note that terminating your cables properly is important to get meaningful and accurate results. Dave did a few videos on that.

author: tunk
author_rank: Super Contributor
timestamp: December 31, 2020, 07:19:46 pm
content: Also remember that the bandwidth is lower with the 1X setting:https://www.eevblog.com/forum/blog/eevblog-453-mysteries-of-x1-oscilloscope-probes-revealed/

author: Muggs
author_rank: Newbie
timestamp: January 08, 2021, 01:53:22 pm
content: Thank you All, lots of great info, I really appreciate it!