The Problem :

When building power electronics or battery management systems, knowing how much current flows through a MOSFET is critical. Without proper current sensing, you risk overheating components or damaging your load.

The Solution :

The simplest solution is placing a low-value shunt resistor in the source path of the MOSFET. By measuring the voltage drop across this resistor, you can calculate the current using Ohm’s Law: I = V / R. Add an op-amp if you need to amplify the small voltage for ADC input.

Practical Example :

Imagine you’re using an N-channel MOSFET to drive a motor. Insert a 0.1Ω resistor between the source and ground. If your microcontroller reads 0.25V across the resistor:

Sample Calculation :

I = V / R = 0.25V / 0.1Ω = 2.5A
So, your motor draws 2.5 amps—easy, right?

Product Suggestion :

For precise builds, use quality MOSFETs and flux (for clean soldering). Both are available as Made in India components:

• MOSFET

• Flux

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