DC current consumption  - Page 1
Forum section: electronics / beginners

author: hpibmx
author_rank: Regular Contributor
timestamp: July 05, 2021, 03:53:48 pm
content: Hi,Im doing smartphone repair mostly IPhone and iPads ,I was wondering if there’s a tool to save my and view my dc current consumption during startup and standby on a motherboard.If oscilloscope does that I don’t have enough experience with it. And I need to get one.If not is there any alternative tool for this?I’ve got my budget logic analyzer it’s on the way shipping, is it possible with it?Sorry for my beginner question.Appreciate your help everyone.

author: antimatter503
author_rank: Contributor
timestamp: July 05, 2021, 04:28:49 pm
content: You probably want a digital multimeter with logging capability.

author: Manul
author_rank: Super Contributor
timestamp: July 05, 2021, 04:57:48 pm
content: I guess you mean consumption from battery? Because consumption from charger would involve battery charging and mess up the measurement. Well, not so easy to do, because you need to tap between battery and device which I guess is physically hard. Some motherboards may have a low value shunt resistor in series with battery for exactly same reason - measure current, implement overcurrent protection and so on. If there is such a shunt on the motherboard, then you could use it by measuring voltage on it. But that also could be hard because the voltage will likely be very small.

author: theHWcave
author_rank: Regular Contributor
timestamp: July 05, 2021, 04:58:46 pm
content: If your power comes from USB, a USB tester can show you the consumption. More advanced ones like the Ruideng TC66 can log it too and have an amazing accuracy for very little money

author: hpibmx
author_rank: Regular Contributor
timestamp: July 05, 2021, 05:26:20 pm
content: No it’s actually without battery connected to the board so connecting dc power supply and measuring capturing the current consumption. In budget way

author: hpibmx
author_rank: Regular Contributor
timestamp: July 05, 2021, 05:27:59 pm
content: I Guess this would really help me a lot.Thank you for recommending I’ll look it up.If they have Pc software would be best. I need.

author: JustMeHere
author_rank: Frequent Contributor
timestamp: July 06, 2021, 02:37:17 am
content: You can always use your O-scope with 2 probes and a shunt resistor. Put the math mode in subtract. Use Ohm's law, the resistance of the resistor, and the voltage drop to calculate the current.https://articles.saleae.com/oscilloscopes/how-to-measure-current-with-an-oscilloscope

author: hpibmx
author_rank: Regular Contributor
timestamp: July 06, 2021, 03:35:52 am
content: This is another good idea thank you for that,which budget Oscilloscope do you recommend for my job? just a basic

author: Andree Henkel
author_rank: Regular Contributor
timestamp: July 06, 2021, 09:07:54 am
content: For measuring the low voltages a scope with smallest Range 0,5mV per division is to be prevered. Some Siglent < 500 seem to do that.Get a Current Sense Amplifier Eval Board: INA180-181EVM by Texas Instruments, Digikey:https://www.digikey.de/products/de/development-boards-kits-programmers/evaluation-boards-op-amps/788?k=ina181ignore the ina181, and you can amplify voltage drop on current sense resistor by 20 / 50 / 100 or 200 before feeding it to scope

author: hpibmx
author_rank: Regular Contributor
timestamp: July 06, 2021, 01:13:47 pm
content: Thank you for your suggestion,Im just working with low voltages like below 10vMost of time 5vAll I need is good software to see the graph for voltage and currentThat would do the job.I’ve been watching about this RD6006 dc power supply which tends to have a software too.Do you think that’s a choice or something similar?I want to be able to see my graph for 2 minute or 5 minute.Thank youI hope I made my self clear ✌🏻