Selecte a Shunt Resistor

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I'm attempting to perform power analysis on my target, which... - Sep 29, 2021 by zxcvb

I've read some articles like https://www.apogeeweb.net/elect... - Sep 29, 2021 by zxcvb

"A shunt is an electrical device that creates a low-res... - Sep 29, 2021 by Stephen

zxcvb

#87146

Selecte a Shunt Resistor | 29 September, 2021

I'm attempting to perform power analysis on my target, which operates at 3.3 volts. The average current while running is around 140mA without the resistor.

With a 5V power source, I utilized a 10Ohm resistor as a shunt resistor. The shunt resistor was connected between 5V and the target VCC pin, and the voltage difference between VCC PIN and GND was measured. (The decoupling caps have been taken out.) The oscilloscope, on the other hand, did not provide a suitable power consumption line.

Is something wrong with my setup? Is there any advice on selecting a shunt resistor?

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zxcvb

#87147

Selecte a Shunt Resistor | 29 September, 2021

I've read some articles like https://www.apogeeweb.net/electron/what-is-a-shunt-resistor.html, but I still have no idea.

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Stephen

#87150

Selecte a Shunt Resistor | 29 September, 2021

"A shunt is an electrical device that creates a low-resistance route for a current to flow through. This allows the current to flow to a different part of the circuit." From that page. It sounds like you are using the resistor in a current limiting capacity. Notice how the article says it allows the current to flow to a different part of the circuit. Your set up isn't doing that the current is still going to the circuit. I think the word shunt originated with rail roads as places to let trains get out of the way. A shunt resistor would let the current go somewhere else. Why not use a 3.3V power supply? Why get rid of the decoupling caps if you are using DC?

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