Tonghui LCR Kelvin Clips TH26011AS, BS, CS? For HP 4274A.

[pac1085]

I recently won an auction for a nice HP 4274A on eBay but need to buy some kelvin clips for it.  I know you can't just use regular kelvin clips with BNC on them since the shields all need to be grounded together.  The HP/Agilent branded one is too much $$ for my homelab.  I read that you can use Tonghui TH26011, however there are 3 variants, AS, BS and CS, and I can't figure out the differences between them.  Any ideas?

Thanks!

[KungFuJosh]

I don't know what the difference is between them, but I have the CS version that came with my LCR, and it's good. The tonghui website is slow, but you should be able to search the model numbers there.

[pac1085]

Thanks,
I did check their site before posting of course.

Their page for TH26011AS says "all LCR digital bridges"
https://www.tonghui.com.cn/en/product_698.html

TH26011BS says "Applicable to: Four-terminal pair instruments such as TH2828, TH2828A, TH2828STH2826, TH2826A can be used with other LCR instruments to obtain better measurement results"

TH26011CS says "Applicable to: TH2830 series, TH2523 series and other LCR instruments except TH2828, TH2838, TH2839 series"

I also wonder if when they say "all LCR digital bridges" it means all of THEIR LCR meters, not necessarily other manufacturers.

unfortunately they do not actually tell you what the difference is, are they wired differently, different bnc spacing ,etc. 
I guess I'll have to try and contact them.  Reality is I've got to order this from China, so I want it to be right the first time since returns won't be a practical option.

[KungFuJosh]

My guess is that their website is stupid, and the real difference might be frequency range support, as that is the defining difference between those models.

I would suggest ordering from and talking to sourcetronic rather than tonghui: https://www.sourcetronic.com/shop/en/kelvin-clip-terminal-st26011c.html

Tonghui is generally terrible about communication and support, and Sourcetronic is the opposite. ST is helpful and responsive.

[pac1085]

OK cool, thanks!  Yea their website listed the same frequency range for all of them

I think I might just order B&K TL89K1, I just found these, digikey stocks them so I can return if I have to, and i found another post here of someone using them on a 4263B, so it should be fine

[mawyatt]

We have the Tonghui TH26011CS that came with our TH2830 LCR meter and the B&K TL89K1. Both Kelvin Clip sets work with the TH2830 and our Hioki IM3536 LCR meters without issue. The B&K are identical to the TH26011CS except for labels, suspect they are just rebranded Tonghui.

Also, the TH26048A leaded fixtures works with both LCR instruments, as does the B&K TL89F1 which is not a rebranded version and comes with two different sets of "inserts" which are handy for different type leaded devices. The Tonghui Shorting Bar works with both sets of leaded fixtures, but with only one type of insert in the B&K.


If you work with SMD devices you'll want to consider these cheap fixtures discussed here.

https://www.eevblog.com/forum/testgear/cheap-smd-lcr-fixture-the-good-bad-and-ugly!/msg4539458/#msg4539458

Best,

[KungFuJosh]

The TL89K1 definitely looks like rebranded TongHui, and that's a good thing - then you don't need to deal with TongHui. 😉