Differential probe on the Siglent 1202x-e - Page 1
Forum section: electronics / beginners

author: CharlotteSwiss
author_rank: Frequent Contributor
timestamp: January 23, 2024, 04:34:07 pm
content: At Christmas I didn't receive any interesting gifts. No problem. I gave myself the Micsig MDP differential probe. I did it for the health of my Siglent 1202x-e, it would have risked a bang sooner or laterTwo problems:One: the probe must be powered by a 5V USB. I don't want to use the USB port on the front of the Siglent, because I would use that for the flash drive. On the back of the 1202-x-e I have a USB type B port (usb device) for connection to the PC, but I have seen that if I connect the probe to that port it is not powered. Is it possible that this USB port doesn't have 5V?Two: with the classic probe, I always connect the black clip to zero potential (ground). When using a differential probe, could I also connect the black probe to a point in the circuit with a voltage? (for example a component in series, I put the black lead at one end, and the other red lead at the other end). I hope I explained myself. Thank you.

author: berke
author_rank: Frequent Contributor
timestamp: January 23, 2024, 06:14:14 pm
content: USB B ports are supposed to receive power, not deliver it. You could try using a small 4-port passive hub.And yes the whole point of a differential probe is that you can connect the - probe to something that has a voltage w.r.t. ground (within reasonable limits.)

author: CharlotteSwiss
author_rank: Frequent Contributor
timestamp: January 23, 2024, 09:02:43 pm
content: Thanks, I didn't know that the USB B port doesn't provide voltage (in fact I measured it and it doesn't have 5V). Patience, I will power the probe from a USB charger.As for where to place the two probe tips, if I understand correctly, for example if we had a rectifier diode, I could put the probe tips on the two ends, both having a voltage?). In short, I would measure the voltage drop signal in the diode. It works like this? Thank you

author: berke
author_rank: Frequent Contributor
timestamp: January 23, 2024, 09:12:38 pm
content: Yes it's like using a voltmeter, it's floating and you get to see what happens over time. But don't exceed the voltage ratings of your probe.

author: CharlotteSwiss
author_rank: Frequent Contributor
timestamp: January 23, 2024, 09:25:40 pm
content: Thanks, it's very kind of you. I won't risk exceeding the rated voltage, with 500x it would be 1500Vpk

author: tautech
author_rank: Super Contributor
timestamp: January 25, 2024, 02:45:02 am
content: Be sure to set the channel input attenuation to that set on the differential probe and engage a P-P measurement then go looking at the 3V 1kHz probe compensation output as a quick and easy sanity check everything is set correctly.

author: CharlotteSwiss
author_rank: Frequent Contributor
timestamp: January 25, 2024, 06:26:03 pm
content: To measure the compensation output, I set the minimum (50x), certainly I will also set it on channel 2. What would P-P be? Peak to peak? But where should I set it?I also have another need: the Micsig probe is supplied with two end tips with hooks as shown in the photo. For certain measurements I would prefer test leads like those of the multimeter (which however do not have a compatible connector). I was looking from the Chinese (Ali@@@@) to buy two traditional pointed tips, without cable, but I can't find anything? Will I search badly?Thank you

author: tautech
author_rank: Super Contributor
timestamp: January 25, 2024, 06:48:49 pm
content: Quote from: CharlotteSwiss on January 25, 2024, 06:26:03 pmYes, select P-P from the Measure menu.Sensitivity is sufficient to display the probe compensation output with 500:1 settings.QuoteGrabber tips are the standard for differential probes due to the elevated voltages they are often used with.Safety first.

author: audiotubes
author_rank: Regular Contributor
timestamp: January 25, 2024, 06:54:40 pm
content: The main cables are banana jacks, so they're compatible with many types of probe tips.Take a look at Welectron, they have a nice selection.

author: CharlotteSwiss
author_rank: Frequent Contributor
timestamp: January 25, 2024, 07:13:40 pm
content: Quote from: tautech on January 25, 2024, 06:48:49 pmOk, I'll try both 50x and 500x, P-P to see if the square wave will be measured accurately enough.Of course, safety first. But even with the multimeter I measure voltages of 400v using traditional test leads. Obvious CAT 1000v tips. Where's the difference? For certain measurements it would seem more convenient to use multimeter type leads, right?

author: CharlotteSwiss
author_rank: Frequent Contributor
timestamp: January 25, 2024, 07:18:33 pm
content: Quote from: audiotubes on January 25, 2024, 06:54:40 pmThanks, I'll look at your advice.In the photo on the left you can see the couplings of the original probe; on the right the original probe, I would like it the same but with the terminal like a multimeter. At home I have two tips with the same connection as those on the right, but that swollen terminal could be dangerous.

author: audiotubes
author_rank: Regular Contributor
timestamp: January 25, 2024, 09:20:33 pm
content: The probes cables that come with the Micsig are standard 4mm banana jacks. They are a good choice, there are countless probes that will work with them.

author: CharlotteSwiss
author_rank: Frequent Contributor
timestamp: January 25, 2024, 10:13:40 pm
content: You're right, but multimeter probes don't fit into the micsig cable. I need to get two probes with a suitable socket. For fast and convenient measurements, traditional probes are more convenient. Especially where you can't get a hook point.

author: CharlotteSwiss
author_rank: Frequent Contributor
timestamp: January 25, 2024, 11:16:43 pm
content: I did some tests with the Micsig MDP differential probe, to check the noise on a low voltage signal (square wave-3v-1Khz). Of course it is not as clean as that of the traditional 10x probe (at the top of the image, yellow), but the 50x one is not bad (in the center of the image, pink) and the 500x one is slightly noisy, but it doesn't seem scandalous to me (bottom of the image, pink).I would like to add that I have enabled bandwidth limitation both in the Siglent (20Mhz) and on the differential probe (5Mhz).I would say satisfied with the purchase.

author: tautech
author_rank: Super Contributor
timestamp: January 25, 2024, 11:22:30 pm
content: Quote from: CharlotteSwiss on January 25, 2024, 11:16:43 pmYes, well you are at 2mV/div sensitivity.Looks good.

author: CharlotteSwiss
author_rank: Frequent Contributor
timestamp: January 25, 2024, 11:34:37 pm
content: Quote from: tautech on January 25, 2024, 11:22:30 pmAnd where do you see this value? Maybe around 200mv? (500x)

author: tautech
author_rank: Super Contributor
timestamp: January 25, 2024, 11:38:38 pm
content: Quote from: CharlotteSwiss on January 25, 2024, 11:34:37 pm1V/div /500:1 = 2mV/div actual input sensitivity.I have used 1000:1 probes with the probe compensation output and still resolve the 3V P-P signal albeit with even a little more noise than you see.

author: CharlotteSwiss
author_rank: Frequent Contributor
timestamp: January 26, 2024, 05:41:31 am
content: Thanks, now I understand. It would be the attenuated voltage at the input BNC. I would say more than acceptable, even limiting the band to 5mhz (there is a specific button on the probe). I would add that however for voltages measured up to 60 Vpk, I will use normal 10x probes. The micsig will be used for medium voltages, such as first image switching. Thank you

author: CharlotteSwiss
author_rank: Frequent Contributor
timestamp: March 12, 2024, 01:51:01 pm
content: I am happy with this MicSig probe, for signals below 5Mhz it is also not very noisy.I generally don't use the two extension cords they provide (30 centimetres).I read in the manual that using the two extensions it would be better to intertwine the two cables? Does all this make any sense?Here's what the MicSig manual says:*Note: Try not to use extension leads when measuring, it could bring more noise floor. If must use theextension leads, please twist the leads together to reduce noise, and the input frequency should notexceed 5MHz. If it exceeds 5MHz, the output will have a certain

author: watchmaker
author_rank: Unknown
timestamp: March 13, 2024, 10:47:11 am
content: I bought this set of Fluke scope probes for $40USD for my diff probe. They have several hundred.https://www.tequipment.net/Fluke/AS400/Misc-Instrument-Accessory-Kits/

author: CharlotteSwiss
author_rank: Frequent Contributor
timestamp: March 13, 2024, 12:35:48 pm
content: Quote from: watchmaker on March 13, 2024, 10:47:11 amHi watchmaker, I already have the accessories for the probe. I just wanted to know from some owners of the MicSig probe model MDPxx the curious note in the manual in case the two extensions supplied are used. It seems curious that it is said to intertwine the cables to have a less noisy signal (truth? Or error in the manual?).(see the official MicSig note I wrote in the previous message).