Timeline for How to measure power (5-500 mW) consumed by low-voltage, low-current device?
Current License: CC BY-SA 3.0
9 events
| when toggle format | what | by | license | comment | |
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| Jul 15, 2020 at 19:24 | vote | accept | Vulcan | ||
| Jan 11, 2017 at 21:19 | answer | added | Vince Patron | timeline score: 3 | |
| Jan 11, 2017 at 19:31 | comment | added | D.A.S. | Change Current Sense R with a switch during each events. to extend the range. 1 Ohm for 50mA and 100 Ohm for 500 uA range. Battery ESR starts around 10 ohms and rises with state of discharge to > 1k | |
| Jan 11, 2017 at 19:22 | comment | added | D.A.S. | to get a 3 decade range with at least 2 significant figures requires a 5 digit measurement or choose 1.5 sigfigs or 2 gain ranges. For a quick and dirty measurement, an Op AMP with a gain of 100 on 50mV and offset null, | |
| Jan 11, 2017 at 19:20 | comment | added | Jasen Слава Україні | sounds like maybe you want to build a transimpedance amplifier, for 60 mA you'll need a fairly strong op-amp. | |
| Jan 11, 2017 at 19:18 | comment | added | D.A.S. | @Vulcan You have the right idea. . Normally a 50mV current shunt is used for full scale, which is gives enough to be sensed without dropping much voltage or dissipating much power.. i.e. efficient yet sensitive enough for DMM. It can be put on either V+ or 0V side for single probe measurements. Due to low battery high ESR, the SMPS pulse voltage drop will be more significant on transients and may affect dropout. Low ESR Caps can reduce this if f is high enough. i.e. Zc(f) is lower than ESR of battery. | |
| Jan 11, 2017 at 19:06 | comment | added | winny | Low cost solution: current clamp + multimeter. High ems solution: Keithley 2281S battery simulator. | |
| Jan 11, 2017 at 18:59 | history | edited | Vulcan | CC BY-SA 3.0 |
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| Jan 11, 2017 at 18:45 | history | asked | Vulcan | CC BY-SA 3.0 |