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Products => Test Equipment => Topic started by: billuanand on October 19, 2015, 12:04:18 pm

Title: cheap currents probes for 20pA to 100 uA
Post by: billuanand on October 19, 2015, 12:04:18 pm
hi,

is there any current probes in 20pA to 100 uA current range with 50MHz bandwidth.

please advice me low cost current probe

and what is the Sensitivity mv/A in current probes, how it relate practically

thank you
Title: Re: cheap currents probes for 20pA to 100 uA
Post by: HighVoltage on October 19, 2015, 12:28:27 pm
The Keysight N2820A comes to mind but it only goes down to 50uA and is NOT cheap
Title: Re: cheap currents probes for 20pA to 100 uA
Post by: LA7SJA on October 19, 2015, 02:53:51 pm
So you want to messure the current from a 3.00 Volt 50 MHz source in a 150 TOhm load? Why? And even  more importantly 20pA to 100uA is a 67dB range, linear from DC to 50MHz and of course cheap!  :-//

The Keysight N2820A has a 3MHz bandwith and it only costs $4,088 the N2821A has a $3,066 price.
If you could only tell us what you are trying to messure, it would be more easy to try and help you.

Johan-Fredrik
Title: Re: cheap currents probes for 20pA to 100 uA
Post by: billuanand on October 20, 2015, 04:05:26 am
i want measure current at gate and drain of FET for current gain measurement. typically current ratings are 20pA to 100uA i want sense this current.
Title: Re: cheap currents probes for 20pA to 100 uA
Post by: BravoV on October 20, 2015, 04:06:14 am
What is your budget limit ?
Title: Re: cheap currents probes for 20pA to 100 uA
Post by: billuanand on October 20, 2015, 04:18:48 am
suitable product as low as possible.

and their is any alternative to measure current using DSO, VNA etc. for this measurement

 
Title: Re: cheap currents probes for 20pA to 100 uA
Post by: BravoV on October 20, 2015, 04:26:19 am
Quote from: billuanand on October 20, 2015, 04:18:48 am
suitable product as low as possible.

1 ? 10 ? 100 ? 1000 ? .. rupee ?
Title: Re: cheap currents probes for 20pA to 100 uA
Post by: billuanand on October 20, 2015, 05:11:28 am
i dnt know about current probes cost, first i want to know is it possible with any product or not.

please advice me, i searched lot for current probes but unable to find in this current range.

thank you.
Title: Re: cheap currents probes for 20pA to 100 uA
Post by: Mechatrommer on October 20, 2015, 05:21:53 am
Quote from: billuanand on October 20, 2015, 05:11:28 am
i searched lot for current probes but unable to find in this current range.
because pA is very rare and highly specialized area... are you in specialized area?
Title: Re: cheap currents probes for 20pA to 100 uA
Post by: billuanand on October 20, 2015, 06:21:58 am
yes, i want measure current at gate and drain of FET for current gain measurement. typically gate current is very low.
 
Title: Re: cheap currents probes for 20pA to 100 uA
Post by: singapol on October 20, 2015, 08:02:57 am
Quote from: billuanand on October 20, 2015, 05:11:28 am
i dnt know about current probes cost, first i want to know is it possible with any product or not.

please advice me, i searched lot for current probes but unable to find in this current range.

thank you.

HP4140B Picoamp meter  and DC voltage source perhaps? Find a cheap working unit or repair it.
    There are modern version of 4140 but can you afford it?

http://www.ebay.com/sch/i.html?_from=R40&_trksid=p2047675.m570.l1313.TR0.TRC0.H0.Xhp4140b.TRS0&_nkw=hp4140b&_sacat=0 (http://www.ebay.com/sch/i.html?_from=R40&_trksid=p2047675.m570.l1313.TR0.TRC0.H0.Xhp4140b.TRS0&_nkw=hp4140b&_sacat=0)
Title: Re: cheap currents probes for 20pA to 100 uA
Post by: Marco on October 20, 2015, 09:55:08 am
FETs with current gain, huh?
Title: Re: cheap currents probes for 20pA to 100 uA
Post by: Mechatrommer on October 20, 2015, 11:15:58 am
he is in "specialized area" allright? he want to measure parasitics, for what is beyond me..
Title: Re: cheap currents probes for 20pA to 100 uA
Post by: Zero999 on October 21, 2015, 10:10:23 pm
Quote from: billuanand on October 19, 2015, 12:04:18 pm
hi,

is there any current probes in 20pA to 100 uA current range with 50MHz bandwidth.

The shot noise at 20pA over a 50MHz bandwidth is 17.9pA so it's not possible to do that with any degree of accuracy.
https://en.wikipedia.org/wiki/Shot_noise#Effects_of_interactions