6. Motor Current Shunt Resistor Selection

1. Component Purpose
The motor draws up to 2A. To detect overload, the controller needs to measure this current. A shunt resistor in the current path creates a small voltage drop proportional to current (V = I × R). The controller’s ADC reads this voltage to calculate current.
At 0.1Ω and 2A: voltage drop = 0.2V (readable by most ADCs). Power dissipated = I² × R = 4 × 0.1 = 0.4W. So the resistor must be rated ≥1W for safe margin.
Required: 0.1Ω · ±1% · ≥1W · 2512 · Current Sense · ±100ppm/°C · −55°C to +125°C · RoHS
2. How to Find It on DigiKey
Go to DigiKey.com → Resistors → Chip Resistor - Surface Mount
Apply these filters:
Resistance → 0.1 Ohms (100 mOhms)
Tolerance → ±1%
Power (Watts) → 1W
Package / Case → 2512
Temperature Coefficient → ±100ppm/°C or better
Part Status → Active
3. Key Specifications & What They Mean
SpecificationRequiredWhy
Resistance0.1ΩGives 0.2V drop at 2A — ADC readable.
Tolerance±1%Current accuracy depends on resistor accuracy.
Power Rating≥1WActual dissipation is 0.4W; 2× margin needed.
TypeCurrent SenseDesigned for low-ohm, stable sensing.
Package2512Large enough to dissipate 0.4W safely.
Temp Coefficient±100ppm/°CLow drift keeps readings stable when hot.
Temp Range−55°C to +125°CStandard industrial range.
RoHSYesCompliance required.
Tip: Metal element resistors generally have better temperature stability than thick film for current sensing applications.
4. Selecting a Safe, Production-Ready Part
The filtered list will show many matching parts. Before you pick one, check: Is it Active? Is stock available? Is the manufacturer reputable? Is a datasheet available?
Full checklist: How to Select a Safe, Production-Ready Component — EWskills Guide
5. Filtered DigiKey Link
➡ View Matching Parts — 0.1Ω, 2512, ±1%, ≥1W, Current Sense

Specification	Required	Why
Resistance	0.1Ω	Gives 0.2V drop at 2A — ADC readable.
Tolerance	±1%	Current accuracy depends on resistor accuracy.
Power Rating	≥1W	Actual dissipation is 0.4W; 2× margin needed.
Type	Current Sense	Designed for low-ohm, stable sensing.
Package	2512	Large enough to dissipate 0.4W safely.
Temp Coefficient	±100ppm/°C	Low drift keeps readings stable when hot.
Temp Range	−55°C to +125°C	Standard industrial range.
RoHS	Yes	Compliance required.

Submit Your Solution

DigiKey Part Number

Search the suitable part on DigiKey and paste the part number. Know more

Please log in to validate part number.

EW AI

EW AI validates your selected part with expert-level precision.

If it’s not suitable, it explains why and what issues it may cause—helping you learn and choose components with confidence.