Applent AT825 LCR teardown & review - Page 1
Forum section: electronics / testgear

author: somlioy
author_rank: Regular Contributor
timestamp: March 03, 2013, 10:54:48 am
content: Heh Applent. Did the fake Apple and Agilent work together on this? O0

author: SeanB
author_rank: Super Contributor
timestamp: March 03, 2013, 12:43:27 pm
content: I will guess if you undo the tape on the battery you will find 2 standard cells inside, each with it's own charge protection board on it. Will be fun after a few dozen charge cycles as to which one will never charge due to capacity differences.

author: firewalker
author_rank: Super Contributor
timestamp: March 03, 2013, 03:27:25 pm
content: No need to scratch off any part number? Nice!Alexander.

author: robrenz
author_rank: Super Contributor
timestamp: March 03, 2013, 03:44:26 pm
content: Cheaper than Agilent and has true 4 wire measurementDoes it have a open/short calibration for compensating for test lead/fixture parasitics?

author: BravoV
author_rank: Super Contributor
timestamp: March 03, 2013, 04:24:14 pm
content: Understand if its marketing/business reason, but technical wise, is it a lot harder to design or make a 100 Khz version vs lower frequency ? Or maybe 100 Khz needs higher tolerance components ?

author: mikeselectricstuff
author_rank: Super Contributor
timestamp: March 03, 2013, 04:50:25 pm
content: Quote from: robrenz on March 03, 2013, 03:44:26 pmYes. Takes about 20 secs for each - suspect it's going through all ranges

author: Unknown
author_rank: Unknown
timestamp: March 03, 2013, 04:57:51 pm
content: This seems to be a decent competitor for the somewhat popular Mastech MS5308. It appears to have similar features (except that the MS5308 gets you 100 kHz for ~$200). The case appears to be nicer and the power supply might actually work, however.

author: mzzj
author_rank: Super Contributor
timestamp: March 03, 2013, 05:37:32 pm
content: Quote from: alm on March 03, 2013, 04:57:51 pmFor europeans Peaktech 2170 is also worth considering. True 4-wire kelvin clips and 4-wire measurement both on banana jack's and "slot" connector.I have had mine for couple of days and I would say I am reasonably satisfied.UI has some quirks that I would do differently and display update rate is somewhat sluggish. But I guess same applies to all Cyrystek-based meters like MS5308 and IET DE-5000.https://www.eevblog.com/forum/reviews/some-photos-from-a-peaktech-2170-teardown/

author: Rufus
author_rank: Super Contributor
timestamp: March 03, 2013, 05:42:27 pm
content: EQU is equivalent circuit series or parallel. The THx secondary is likely Theta or phase angle.LCR meters stimulate the unknown impedance through a known impedance at a particular frequency and measure the relative voltage amplitude and phase across the unknown.All you get is the two numbers representing the complex impedance of the unknown. They then provide a lot of ways of representing that impedance most commonly as the values of perfect L or C with R in series or parallel which would produce the same complex impedance (the equivalent circuit of perfect components). Impedance Z and phase angle Theta is the most direct display of what is actually being measured.

author: Hydrawerk
author_rank: Super Contributor
timestamp: March 03, 2013, 07:10:45 pm
content: This Applent AT825 is too complicated, therefore it might be not much reliable... It has about twenty-eight integrated circuits inside... What the hell? My DT-9935 hasfourICs...https://www.eevblog.com/forum/testgear/cheap-lcr-meter-cem-dt-9935/msg194934/?topicseen#msg194934There is another LCR meter based on the same chipset, probably.http://youtu.be/ji-UT7HJm0Q?t=8m51sIt looks much more reliable!

author: Unknown
author_rank: Unknown
timestamp: March 03, 2013, 07:13:48 pm
content: It uses a two-chip Cyrustek ASIC. No wonder that it contains much less parts. Good luck repairing it if one of those ASICs blows up, however.

author: Hydrawerk
author_rank: Super Contributor
timestamp: March 03, 2013, 07:18:30 pm
content: And here is Appa 703 internal circuitry.https://plus.google.com/photos/104378593109746079667/albums/5601643946056628337?sqi&sqsi

author: mzzj
author_rank: Super Contributor
timestamp: March 03, 2013, 07:22:55 pm
content: Quote from: Hydrawerk on March 03, 2013, 07:10:45 pmThis sounds like old MIL-Spec reliability analysis: More parts make it less reliable even if those extra parts would be for protection...I bet this Agilent looks unreliable also:Or BK Precision 879B for that matter, way too much parts. Tonghui version of basically same BK Precision meter is even worse because it has 1pcb full of extra components. (Input protection components...)Actually I am a bit worried about Cyrystek-based meters like DT9935. Input connectors are quite directly connected to speciality chip, compared to bunch of garden variety chips in BK 879B for example.

author: Unknown
author_rank: Unknown
timestamp: March 03, 2013, 07:28:24 pm
content: Both use the Cyrustek chipset that is used in a lot of recent handheld LCR meters: IET DE-5000, Mastech MS-5308, the DT-9935 and Appa you show and a Uni-T LCR meter. I'm sure this is not an exhaustive list. The Applent uses a different (older?) design with less integration. This means it will offer different features / specs from the dime a dozen Cyrustek models, which may be both good or bad.

author: Hydrawerk
author_rank: Super Contributor
timestamp: March 03, 2013, 07:41:50 pm
content: OK, DT-9935 is not perfect. Especially in input protection.But I hope that other LCR meters based on Cyrustek chipsets have someway better input protection.I bought DT-9935, because it was super cheap.

author: Unknown
author_rank: Unknown
timestamp: March 03, 2013, 08:25:25 pm
content: I wouldn't count on it. I know the IET DE-5000 lacks any input protection, so I'm sure the Cyrustek reference design doesn't have it either.

author: M. András
author_rank: Super Contributor
timestamp: March 03, 2013, 08:42:15 pm
content: looks like a good deal if its remain within specs, btw if you ever need it can this thing be calibrated? wondering about how close can this read to a calibrated lcr bridge

author: martinv
author_rank: Contributor
timestamp: December 25, 2013, 08:07:44 am
content: I picked up an AT825 and it appears to have issues. The measurements seem to be way off when using the supplied probes (ATL501C fixture). After running the open/short cal routine, a 1 ohm resistor measures 23 ohms and a 10 ohm resistor measures 1.6Megaohms!.I ohmed out all connections and it appears to be OK. inside the unit looks ok also.The strange thing is when I insulate the guard terminals the meter seems to read correctly (or much closer). Inside the probe 2 guard terminals are directly connected to each other and also to the lower "L" (black) terminal. When plugged into the meter, a connection is then made from the lower "L" terminal to the guard terminals. Somehow bridging these grounds is causing an issue.The unit came with a test report including the serial number showing all the ranges were tested to be within spec, but it does not mention if the probes were used for these measurements.

author: martinv
author_rank: Contributor
timestamp: February 22, 2014, 08:53:10 pm
content: Update. I had to send my meter back to China. $60 shipping! (included signature confirmation as I didn't want it to "dissapear")I was afraid I would get it back with the same issue and some explanation "unit tested OK.." However they actually fixed it and it appears to be working perfectly.I wonder what was wrong and what they actually fixed.. The eBay seller could barely speak English so I didn't bother to ask.

author: Feuerbard
author_rank: Contributor
timestamp: November 06, 2015, 02:15:07 pm
content: some internal photos

author: MetalHead
author_rank: Contributor
timestamp: July 29, 2025, 11:39:22 am
content: Where is an ADC on this board? It's a separate chip or its inside of uC? I have this unit and it complains that ADC failed