Re: [EE] measuring the magnetic field from a small trace carrying a < 50uA load?
"Harold Hallikainen" <[email protected]>
| Newsgroups | gmane.comp.hardware.microcontrollers.pic |
|---|---|
| Message-ID | <[email protected]> |
Modulating the current is an interesting idea. But then you'd also get current in the bypass capacitors. The earth's magnetic field really messes up DC current measurement. I have a clamp on DC ammeter that I have to constantly re-zero as I move it around. A way that I found shorts on boards (at least power supply shorts - much higher current) is to measure the voltage across a trace. Microamps and milliohms gives a pretty small voltage. And, you don't know the trace resistance, so a higher voltage drop does not necessarily mean a higher current (it could be a higher resistance). Slash and burn may be it! Harold On Thu, January 2, 2025 6:11 pm, David VanHorn wrote: > Can you modulate the current? Otherwise slash and burn may be required. > > On Thu, Jan 2, 2025, 6:05â¯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 > -- Not sent from an iPhone. -- http://www.piclist.com/techref/piclist PIC/SX FAQ & list archive View/change your membership options at https://mailman.mit.edu/mailman/listinfo/piclist