Why is high frequency fidelity information desirable here? I would think that an inrush measurement would be made with a sweep no faster than 0.1 millisecond per division. If you are interested in something faster than that you also need to stabilize and standardize the line impedance.
> From: "Richard Hughes" <[email protected]> > Reply-To: "Richard Hughes" <[email protected]> > Date: Wed, 18 Feb 2004 00:10:08 +0000 > To: "Gary McInturff" <[email protected]> > Cc: "'Price, Ed'" <[email protected]>, "'EMC PSTC'" <[email protected]> > Subject: RE: DC Current Probes > > > Gary, > > I agree that the brass blocks you mention are OK for low frequencies, > but they often use relatively long conductors so inductance could be a > problem. Also a possible problem at higher frequencies is the added > inductance introduced by the time you have run wires to these blocks. > > > My suggestion would be to use four terminal precision current sensing > resistors wired as close to the pcb as possible. Such devices are > available from Rhopoint in the UK and probably other companies in the US > too. The resistance starts at 1 mohm, which is probably less than you'd > get from hooking up a great big bass block. This solution is likely to > be higher cost however. As always, you pays your money and takes your > choice. > > Surface mount type: http://www.rhopoint.co.uk/components/RHPM/rhpm.htm > > Leaded type: http://www.rhopoint.co.uk/components/LORL/lorl.htm > > [I have no connection with the above company, other than I have used > their products in the past.] > > Regards, > > Richard Hughes > > Safety Answers Limited > www.safetyanswers.ltd.uk > > Gary McInturff wrote: > >> >> I was wondering the same thing. You can get brass blocks that drop mV per >> lots of amps linearly. They come in different sizes and offer almost no >> impedance at DC or higher freq's. DVM's or O-scopes are hooked in >> parallel >> with the blocks and the small voltage drop monitored. They handle lots of >> power and are pretty cheap. >> Am I missing something (again?) >> Gary >> >> -----Original Message----- >> From: Price, Ed [mailto:[email protected]] >> Sent: Tuesday, February 17, 2004 7:52 AM >> To: 'EMC PSTC' >> Subject: RE: DC Current Probes >> >> >> >> >>> -----Original Message----- >>> From: Finlayson Joseph-G3162C [mailto:[email protected]] >>> Sent: Tuesday, February 17, 2004 5:54 AM >>> To: 'EMC PSTC' >>> Subject: DC Current Probes >>> >>> >>> >>> Group, >>> >>> I am looking to source a DC current probe to measure >>> steady state as well as inrush currents for a modular chassis >>> up to 100 Amps DC. >> >> >> Joe: >> >> Do you REALLY need a current probe? Can't you do this with a resistive >> shunt >> and an oscilloscope, using either differential inputs or simply >> floating the >> scope? >> >> That said, some of the widest bandwidth current probes (like 3 dB down >> at 5 >> Hz, very flat response, 1% accuracy) are available from Pearson >> Electronics: >> http://www.pearsonelectronics.com/ . Unfortunately, I don't know of a 100 >> Amp DC current sensor; all the Tek or HP probes (Hall effect or >> magnetoresistive) that I've seen are limited to about 6 Amps or so. >> >> >> Ed >> >> >> Ed Price >> [email protected] WB6WSN >> NARTE Certified EMC Engineer & Technician >> Electromagnetic Compatibility Lab >> Cubic Defense Applications >> San Diego, CA USA >> 858-505-2780 (Voice) >> 858-505-1583 (Fax) >> Military & Avionics EMC Is Our Specialty >> >> ------------------------------------------- >> This message is from the IEEE EMC Society Product Safety >> Technical Committee emc-pstc discussion list. >> >> Visit our web site at: http://www.ieee-pses.org/ >> >> To cancel your subscription, send mail to: >> [email protected] >> with the single line: >> unsubscribe emc-pstc >> >> For help, send mail to the list administrators: >> Ron Pickard: [email protected] >> Dave Heald: [email protected] >> >> For policy questions, send mail to: >> Richard Nute: [email protected] >> Jim Bacher: [email protected] >> >> All emc-pstc postings are archived and searchable on the web at: >> http://www.ieeecommunities.org/emc-pstc >> >> ------------------------------------------- >> This message is from the IEEE EMC Society Product Safety >> Technical Committee emc-pstc discussion list. >> >> Visit our web site at: http://www.ieee-pses.org/ >> >> To cancel your subscription, send mail to: >> [email protected] >> with the single line: >> unsubscribe emc-pstc >> >> For help, send mail to the list administrators: >> Ron Pickard: [email protected] >> Dave Heald: [email protected] >> >> For policy questions, send mail to: >> Richard Nute: [email protected] >> Jim Bacher: [email protected] >> >> All emc-pstc postings are archived and searchable on the web at: >> http://www.ieeecommunities.org/emc-pstc >> > > > > ------------------------------------------- > This message is from the IEEE EMC Society Product Safety > Technical Committee emc-pstc discussion list. > > Visit our web site at: http://www.ieee-pses.org/ > > To cancel your subscription, send mail to: > [email protected] > with the single line: > unsubscribe emc-pstc > > For help, send mail to the list administrators: > Ron Pickard: [email protected] > Dave Heald: [email protected] > > For policy questions, send mail to: > Richard Nute: [email protected] > Jim Bacher: [email protected] > > All emc-pstc postings are archived and searchable on the web at: > http://www.ieeecommunities.org/emc-pstc > This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. 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