Re: [EE] measuring the magnetic field from a small trace carrying a < 50uA load?
smplx <[email protected]>
| Newsgroups | gmane.comp.hardware.microcontrollers.pic |
|---|---|
| Message-ID | <[email protected]> |
Thinking about core memory: how about using a small ferrite core with a sense wire and write wire through it. energise the write wire to set up a field in one direction then bring the core next to the trace and measure how long it takes to switch magnetic field direction. or maybe how much current you need to apply in the other direction to change magnetic polarity. or something like that. you'd obviously need to calibrate your probe against known sources. Look at how small ferrite cores were (towards the end of their reign) and how little current they used to change state. Regards Sergio Masci On Fri, 3 Jan 2025, Chuck Olson wrote: > Do you have an old busted cassette recorder ? Maybe the playback head > could be used to sense the field ? > > On Thu, Jan 2, 2025 at 7:05 PM Jason White > <[email protected]> wrote: >> >> When developing battery powered devices, sometimes it can be difficult to >> track down where the last few dozen microamps of load are being drawn. >> >> One can resort to systematically cutting traces and desoldering components. >> But that is destructive, labor intensive, and error prone. >> >> I would like to know if an active probe exists that can measure and >> discriminate the current/DC magnetic field of small < 50uA loads on small >> but loosely packed PCB traces. >> >> Are there other viable (hopefully nondestructive) ways to track down small >> loads? (A low noise thermal camera in a vacuum chamber?) >> >> -- >> Jason White >> -- >> http://www.piclist.com/techref/piclist PIC/SX FAQ & list archive >> View/change your membership options at >> https://mailman.mit.edu/mailman/listinfo/piclist > > -- > http://www.piclist.com/techref/piclist PIC/SX FAQ & list archive > View/change your membership options at > https://mailman.mit.edu/mailman/listinfo/piclist -- http://www.piclist.com/techref/piclist PIC/SX FAQ & list archive View/change your membership options at https://mailman.mit.edu/mailman/listinfo/piclist