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Current Sense Resistor & Shunt Calculator
Calculate shunt voltage, resistor power dissipation, current-sense amplifier output, and tolerance/TCR error for current measurement circuits in power supplies, motor drives, battery systems, and embedded electronics.
Input Parameters
Results
Equations Used
Sense Voltage: Vsense = I × Rshunt
Shunt Power: P = I² × Rshunt
Amplifier Output: Vout = Vsense × gain
Resistance Error Estimate: total error ≈ tolerance + TCR × ΔT / 10,000
Frequently Asked Questions (FAQ)
Q1: How do I choose a current sense resistor?
Select a value that gives enough sense voltage without excessive power loss or voltage drop.
Q2: Why is shunt resistor power important?
Power dissipation heats the resistor, changes resistance through TCR, and can exceed the resistor package rating.
Q3: What sense voltage is typical?
Low-side and high-side current sense circuits often use tens of millivolts to a few hundred millivolts depending on accuracy and power loss requirements.
Q4: Does this include amplifier offset error?
No. Add current-sense amplifier offset, gain error, input bias, PCB thermocouple effects, and ADC error for a full error budget.
Q5: Can this be used for BMS and motor drives?
Yes for first-order shunt sizing, but surge current, pulse power, Kelvin layout, and temperature must be validated.
