Acoustical & Electrical Engineering Tool
Membrane Trace & Conductor Resistance Calculator
Design and size your planar voice-coil traces. Calculate the exact DC resistance ($R_e$) to verify safe amplifier loading and estimate total moving conductor mass before cutting foil.
Membrane Trace Resistance Calculator
Pouillet's Law • Pure DC Voice-Coil Load Calculation
Standard: 9µm – 18µm foil | 35µm = 1oz Cu
Total Resistance
5.11 Ω
Custom Load
Conductor Mass
4.80 g
Excludes film substrate
Cross Section
0.096 mm²
Per conductor lane
How the Math Works: Pouillet's Law
The electrical resistance of any straight or serpentine conductor on a loudspeaker diaphragm is governed by Pouillet's law:
R = ρ · ( L / A )
- ρ (Material Resistivity): 2.65 × 10⁻⁸ Ω·m for pure Aluminum; 1.68 × 10⁻⁸ Ω·m for pure Copper.
- L (Conductor Path Length): The total unwound length of all serpentine winding passes across the active membrane.
- A (Cross-Sectional Area): Width of the foil trace multiplied by the foil thickness.
Key Design Guidelines for Planar Diaphragms:
Target 3.5 Ω – 4.2 Ω Nominal Load
Most solid-state and Class D amplifiers prefer nominal 4 Ω or 8 Ω loads. Avoid dropping below 2.5 Ω unless using a dedicated step-up ribbon transformer.
Minimize Moving Conductor Mass
The lighter the total moving conductor mass (foil + film substrate), the higher the acoustical efficiency, transient rise time, and high-frequency extension.