Can Active or Differential Probe get Damaged If... - Page 1
Forum section: electronics / testgear

author: Mechatrommer
author_rank: Super Contributor
timestamp: November 29, 2018, 11:49:07 am
content: i have WL600 with D500PT head Differential Probe. i am wondering before doing it... can the head got damaged by applying signal to the input while its turned off? as if while probing active circuit on DSO, and then disconnect the probe to change channel, since its powered from DSO, it will turned off for a while while changing port channel but the tips are still connected to active circuit and voltage. can i screwed up by doing this?

author: BravoV
author_rank: Super Contributor
timestamp: November 29, 2018, 11:51:05 am
content: Subbed, really like to know too.

author: Mechatrommer
author_rank: Super Contributor
timestamp: November 30, 2018, 12:55:59 pm
content: maybe my question is a little bit too difficult to answer since its specific to D500PT. i was not specific to Lecroy or D500PT head, i was meant to ask active (or differential) probe in general any type or brand or BW, but it must be DC coupled, i guess AC coupled probe will not get harmed on this situation, anyone? where's all those old time HF/signal integrity experts and friends around here, i missed you all.

author: DaJMasta
author_rank: Super Contributor
timestamp: November 30, 2018, 04:55:18 pm
content: Don't know about those probes specifically, but of course it's possible to damage them. If you've got a FET probe, for example, you just need to get enough voltage to get the junction to breakdown and carry current, which anything outside the spec of the probe or high enough ESD would certainly damage it.My guess is that you mean if regular circuit voltages could damage it if powered off.... and I guess that's a trickier one to answer unless you know the architecture of the probe. I doubt any manufacturer recommends it, though. Looking through the manual for a LeCroy HFP2500, the say not to leave it connected to a voltage source if it's not connected to a scope, but they don't say if the scope has to be on - could just be to prevent floating issues when reconnecting to a grounded scope.

author: David Hess
author_rank: Super Contributor
timestamp: December 02, 2018, 01:08:01 am
content: It depends on the design of the probe. Some are protected whether powered (or grounded) or not.

author: Mechatrommer
author_rank: Super Contributor
timestamp: December 14, 2018, 03:17:59 pm
content: Quote from: BravoV on November 29, 2018, 11:51:05 amlet me answer OP (my own) question... D500PT will not get damaged by doing so. tried on 0.7Vpp signal, pulled out of the socket and put back in another socket, still workingAP020 is coming to be tested soon, hopefully it will arrive

author: BravoV
author_rank: Super Contributor
timestamp: December 14, 2018, 04:14:03 pm
content: Thanks pakcik, looking forward to see your new toy result.

author: Mechatrommer
author_rank: Super Contributor
timestamp: December 14, 2018, 04:21:52 pm
content: Quote from: BravoV on December 14, 2018, 04:14:03 pm"The First Capture"... probing 125MHz clock and 2GHz output of ADF4355 china RFGen...iirc beyond 3GHz its not pretty but i didnt capture. i suspect something wrong with ADF4355 output/filter or my probing technique but not sure whatedit: my memory served me incorrectly, the signal 1GHz and greater is fine, except flatten out at 6GHz (bricked wall in the scope or the RFGen LF filter not sure), the bad signal is lower than 1GHz since the RFGen out is actually AC coupled so square wave out of synthesizer got distorted by HF filter part. this was just a quick test to see if my new toy and probe is working as claimed by the ebay sellers before giving them +ve feedbacks. still a lot to learn waiting ahead