Testec TT-CC 550 current probe - hackable? - Page 1
Forum section: electronics / testgear

author: tatus1969
author_rank: Super Contributor
timestamp: July 09, 2019, 09:33:45 am
content: I've just upgraded from my Hantek CC-65 (20kHz) to this 500kHz probe, only to realize that I still need more bandwidth (well, stupid decision anyway, how did I expect to measure the inductor current of a 500kHz step down with a 500kHz probe? But I digres...)Testec has made an entire family of current probes, ranging from 300kHz to 1.5MHz but looking identically otherwise. I wonder if these are hackable with regards to the usable bandwidth, in a similar way like e.g. the Siglent SDS2000X family (just did that to my SDS2074X yesterday, works perfectly) ??I'm tempted to open mine and see myself, but I don't want to get in trouble with the seller when wanting to return it and purchase an upgrade.

author: tautech
author_rank: Super Contributor
timestamp: July 09, 2019, 09:49:06 am
content: Current probes are buy once cry once tools.With the savings made on your 300 MHz DSO splash out and buy once for a lifetime of use and trustworthiness !After cobbling a current probe together from a CT off an old ATX PCB that worked well enough into the 10's of KHz I saved up and waited for a Tek 60 MHz P6021 on eBay for a reasonable price then pounced. Still have it many years later.

author: capt bullshot
author_rank: Super Contributor
timestamp: July 09, 2019, 09:52:49 am
content: Can't tell from the datasheets / manuals if these are open or closed loop.In case of open loop, there might be a different sensor (or the sensor biased at different currents), in case of closed loop there will be a different number of turns on the secondary.One could measure the current draw from the battery - if this is constant and independent of primary current, it's open loop, if the current draw is kind of proportional to the primary current, it's closed loop.

author: tatus1969
author_rank: Super Contributor
timestamp: July 09, 2019, 10:04:09 am
content: The higher BW models state shorter battery life, that could be a hint. But these are AC+DC, so probably some hybrid form. The TEK P6021 is AC only AFAIK.

author: capt bullshot
author_rank: Super Contributor
timestamp: July 09, 2019, 10:12:14 am
content: Yes, shorter battery life would point into open loop / different sensor or higher bias direction. Also the rather not-so-accurate specifications make me think these are open loop.A6302 + AM503 is what you want:http://w140.com/tekwiki/wiki/A6302Or, if you can spare the money, one of their modern equivalents made by Hioki and rebranded/sold by all big names (Yokogawa, Tek, Agilent, LeCroy).

author: tautech
author_rank: Super Contributor
timestamp: July 09, 2019, 10:14:06 am
content: Quote from: tatus1969 on July 09, 2019, 10:04:09 amCorrect.120 Hz to 60 MHz, 15 A p-p sine wave between 300 Hz and 5 MHz

author: nctnico
author_rank: Super Contributor
timestamp: July 09, 2019, 10:17:38 am
content: A bit of a shameless plug but one of my products is a dual channel current probe you can wire in between. The bandwidth exceeds 10MHz and it probably costs less compared to the Testec.

author: tatus1969
author_rank: Super Contributor
timestamp: July 10, 2019, 03:44:10 am
content: A6302 + AM503 is a dream, but still is 1800€ combined and above my budget. Just ordered that 1.5MHz probe now