Plagiarize Keysight  b2983 - Page 1
Forum section: electronics / general

author: ssmsc
author_rank: Newbie
timestamp: August 09, 2022, 11:33:13 am
content: [ Specified attachment is not available ]I especially despise this kind of behavior！

author: Echo88
author_rank: Frequent Contributor
timestamp: August 09, 2022, 01:57:12 pm
content: https://www.tonghui.com.cn/en/product_1126.htmlI suppose its this one?https://www.keysight.com/us/en/assets/7018-04484/data-sheets/5991-4878.pdfFor comparison

author: ssmsc
author_rank: Newbie
timestamp: August 10, 2022, 04:34:00 am
content: Quote from: Echo88 on August 09, 2022, 01:57:12 pmYou are absolutely right

author: MegaVolt
author_rank: Frequent Contributor
timestamp: August 11, 2022, 09:10:15 am
content: Quote from: ssmsc on August 09, 2022, 11:33:13 amWhere are these photos from? Is there any discussion on another forum? Or a review?

author: r6502
author_rank: Regular Contributor
timestamp: August 11, 2022, 11:29:11 am
content: hello all,have a look here:https://xdevs.com/review/b2987a/Very detailed review with lots of photos. need to have equipmentGuido

author: MegaVolt
author_rank: Frequent Contributor
timestamp: August 11, 2022, 12:02:51 pm
content: Quote from: r6502 on August 11, 2022, 11:29:11 amI was interested in the review on the TH2690, whose photo is very similar to the B298xA.

author: thm_w
author_rank: Super Contributor
timestamp: August 11, 2022, 11:06:45 pm
content: Rotated so its easier to compare

author: alm
author_rank: Super Contributor
timestamp: August 12, 2022, 12:19:42 am
content: Interesting how Tonghui skimped on the guard ring around the (presumably very high impedance) nodes with the high value thin film resistors to the point where the ring around R103 has barely any copper around the vias. Funny how on the Tonghui board they added footprints for extra resistors in case they needed to adjust something, while Keysight probably had the resistors made to spec. It also looks like the the TH board might have fewer layers, although that could be the lighting.

author: MegaVolt
author_rank: Frequent Contributor
timestamp: August 12, 2022, 08:32:48 am
content: They replaced the main partThe vacuum capacitor was replaced with some kind of rubbish.

author: Kleinstein
author_rank: Super Contributor
timestamp: August 12, 2022, 09:05:33 am
content: There is obvious similarity in the layout, but there are still differences: the Tonghui meter has 1 range less and the case / connectors are also different with inputs at the front instead of the back.A decade lower sensitivity also means they can get away with more.The extra footprint for a 2nd parallel high ohms resistor is odd, expecially with the same size. It would make some sense for a different size, but not this way. For a trim a sereis resistor is there an much more conventient.Somehow both designs do not try to really keep the critcal node compacs / small.

author: thm_w
author_rank: Super Contributor
timestamp: August 12, 2022, 09:43:49 pm
content: Quote from: Kleinstein on August 12, 2022, 09:05:33 amThe bottom one is marked as a capacitor.Top one I can't see.

author: Echo88
author_rank: Frequent Contributor
timestamp: August 12, 2022, 09:58:32 pm
content: The 3pF capacitor is a vacuum type? Do you have a partnumber/datasheet for it MegaVolt?

author: thm_w
author_rank: Super Contributor
timestamp: August 12, 2022, 10:22:35 pm
content: Quote from: Echo88 on August 12, 2022, 09:58:32 pmTiN calls it:Quotehttps://www.eevblog.com/forum/metrology/keysight-b2980a-series-electrometerpicoammeter-teardown/https://xdevs.com/doc/HP_Agilent_Keysight/B2987A/img/bem_eaucap.jpg

author: ssmsc
author_rank: Newbie
timestamp: August 14, 2022, 10:45:08 am
content: Tonghui should not understand the key technology of low current measurement.

author: MadTux
author_rank: Frequent Contributor
timestamp: August 17, 2022, 10:22:36 pm
content: Lol, still managed to clone it, even with service manuals unavailable.Take that Keysight and anyone else with no schematics available, for making honest repairs much more difficult.

author: julian1
author_rank: Frequent Contributor
timestamp: August 18, 2022, 10:27:49 pm
content: A comment on both boards. It is curious to see all the guarding, and cutouts, while also employing signal relays (datasheet suggests 1G insulation resistance), rather than reed relays.Maybe the signal relay coils, and pole node, are driven by isolated/floating signal relays. The digital board of the agilent has a bunch of reed relays, so perhaps that is the strategy used.

author: bsw_m
author_rank: Frequent Contributor
timestamp: August 19, 2022, 04:45:34 pm
content: Quote from: julian1 on August 18, 2022, 10:27:49 pmThe AGN210 series relays are adequate for the application of this device. They have an insulation resistance between open contacts > 100 PetaOhm and an insulation resistance between the coil and all shorted contacts > 100 TeraOhm. (Data from actual measurements of a certain number of these relays)These relays also provide reliable contact for switching low currents/voltages.The main disadvantage of these relays is the absence of an electrostatic shield between the coil and the contact groups, so that they have a very high charge injection from the control (when the relay is switched).P.S. The Hongfa relays used in the Tonghui electrometer have comparable parameters with the Panasonic AGN210 series relaysP.P.S. For comparison, the insulation resistance between the open contacts of the electrometric reed relay TRY-204S-14 manufactured by Okita is about 2 PetaOhm

author: RLiangCN
author_rank: Newbie
timestamp: June 05, 2024, 07:29:52 am
content: Quote from: bsw_m on August 19, 2022, 04:45:34 pmHi, thanks for your information.I wonder if the same series AGN200 relays (single side relays) have the same insulation performance as the AGN210 series? In my design, it's a bit difficult to provide polarity-reversed driving signal...(I have already ordered AGN200S4H, and plan to test its performance when I get it)And there's another question, what kinds of relays (or key specifications) should be considered first for an electrometer application?

author: bsw_m
author_rank: Frequent Contributor
timestamp: June 05, 2024, 08:18:12 am
content: Quote from: RLiangCN on June 05, 2024, 07:29:52 amReliable contact at low currents; insulation resistance; charge injection when relay switching - preferable shielded relays.