Author Topic: First time using Ucurrent gold, needs some expert advise :)  (Read 951 times)

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Offline Henry_jkTopic starter

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  • Country: ca
First time using Ucurrent gold, needs some expert advise :)
« on: October 02, 2018, 08:00:37 pm »
Hi Everyone,

I just bought an Ucurrent gold to measure Sleeping current one a circuit that I design.  The circuit comprised of ESP8266 and Attiny sends a signal to a 2n7000 that turn on or off the power to the ESP8266.  The Attiny 84 sleeps majority of the time, while the ESP is powered off.

So I bought the Ucurrent gold with the hope to measure the low current of my entire circuit while it's asleep.  The problem that I encounter is when I hook up the uCurrent gold according to this setup (please see diagram). It seems like the burden voltage on my DMM still effects the ESP8266. The blue light flickers, but it doesn't seem to perform its actual duty.

My circuit has two states, active state (awake and do something), sleep state (almost everything is off except the attiny84). When I use the Ucurrent gold to measure the active state (draws 50-120mA typically when esp is on), the esp doesn't seem to function or connect to the web. The blue light flickers.

I have tried to measure the resistance on the Current IN, and Out with 10K 10Ohm and 10mOhm they all seem to read correctly. So I don't think I blew the Shunt resistor.

So I draw a diagram to illustrate my setup. I hope I didn't damage anything :(
Any feedback would be much appreciated.
 

Offline Henry_jkTopic starter

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  • Posts: 3
  • Country: ca
Re: First time using Ucurrent gold, needs some expert advise :)
« Reply #1 on: October 03, 2018, 10:37:06 pm »
Or perhaps if anyone would able to tell me if my diagram is correct?

Much appreciated.
 

Offline piguy101

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  • Country: us
Re: First time using Ucurrent gold, needs some expert advise :)
« Reply #2 on: October 04, 2018, 12:15:38 am »
I don't own a uCurrent, but it looks like you've got the uCurrent wired up so that your DMM will read negative currents. That shouldn't be an issue, but this is just a heads up.

What range do you have the uCurrent on? The burden voltage might be too high when the microcontroller is active. Assuming you have it on uA range (middle range), there is a resistance of 10 Ω. 100 mA through 10 Ω is a 1 V drop in voltage, which is likely unacceptable for your circuit.
 


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