Current Probe for GW121? - Page 1
Forum section: electronics / testgear

author: mtgstuber
author_rank: Newbie
timestamp: September 10, 2023, 07:23:16 am
content: Hi folks,I just picked up a GW121, primarily for the logging capabilities. I considered the Keysight 12xx series, but there didn't seem to be a way to do interval logging without connecting a phone or computer. I considered the Fluke 287/289, but didn't really want to spend that much, given that I have a series of other meters. I liked the open nature of the GW121.I'm interested in picking up a current clamp / current probe for the GW121. I don't really need high currents. I have two other clamp meters, but they don't do data logging.Any thoughts on a clamp probe that I could use with the GW121? I'm primarily interested in being able to log currents in household and automobile applications. 30 or 40 A is fine for an upper limit -- in fact it's preferred, as I'm interested in more low end detection capability.

author: Kleinstein
author_rank: Super Contributor
timestamp: September 10, 2023, 07:28:36 am
content: For AC there are relatively cheap external current clamps that give out a proportional voltage. One can also use some kind of DIY or commercial current transformer.For DC things are more complicated as a DC current clamp needs an active circuit and can be tricky with small currents as an external magentic field can effect the readings.

author: BILLPOD
author_rank: Frequent Contributor
timestamp: September 10, 2023, 01:12:25 pm
content: The clamp accessory that pairs with the new Uni-T UT117c DMM also works with my 121GW, on the mV range. Good to 400A AC, (no DC).It is model # UT-CS06A and is only around $20 USD.

author: mendip_discovery
author_rank: Super Contributor
timestamp: September 10, 2023, 02:28:18 pm
content: I have yet to find a sensible clamp meter. I might get some shunts but they are a bit of a pain when working in a vehicle and all you want to do is log the current as you change the rpm.I would say I am looking at <200A.I did buy an amazon cheap thing but I have yet to get repeatable numbers with it.

author: bicycleguy
author_rank: Frequent Contributor
timestamp: September 12, 2023, 12:13:34 am
content: A Micsig CP2100A works great using a bnc to plug adapter and is even better with an oscilloscope for when you need to see what's really going on.

author: J-R
author_rank: Super Contributor
timestamp: September 12, 2023, 07:21:02 am
content: Most scope probes like the Micsig use USB for power and also have relatively long leads. This is fine for bench use but a bit obnoxious otherwise in my opinion, compared to a battery-powered unit. But maybe your use case demands constant power...I found some reasonably priced DMM current clamp options on ebay:Lutron CA-501 -https://www.ebay.com/itm/175332271175Fluke i410 -https://www.ebay.com/itm/235194669723CA-60 -https://www.ebay.com/itm/314783580198https://www.ebay.com/itm/364389082567Mac Tools EM121 -https://www.ebay.com/itm/186066308842I have both the CA-60 and the Micsig CP2100B. Accuracy is a bit tricky. DC clamps like to be zeroed constantly... A shunt resistor is the better option if at all possible.

author: Jeroen3
author_rank: Super Contributor
timestamp: September 12, 2023, 10:00:47 am
content: There is the occasional fluke i30s for sale on ebay for a lot of money.

author: Njk
author_rank: Frequent Contributor
timestamp: September 12, 2023, 11:26:02 am
content: What about Hantek CC-65? It's extensively reviewed here, with all the schematics and comprehensive modding instructions. Still in production.https://www.eevblog.com/forum/testgear/hantek-cc-65-acdc-current-probe-teardown-and-testing/