Use this electronics calculation for a first-pass component, converter, signal, motor, or sensor estimate when the stated operating conditions and units match the device data.

Resistivity (ohm*m)

Required number input.

Compute electrical conductivity in siemens per meter as the reciprocal of resistivity. The tool evaluates the supplied inputs together and returns the named outputs below; it does not infer omitted operating conditions or change the units shown.^[1]

Conductivity (S/m)

The resulting conductivity returned as a number.

• Resistor value, power, noise, and color-code calculations must account for tolerance, temperature coefficient, voltage coefficient, pulse rating, working voltage, package thermal resistance, ambient temperature, and mounting. Required steady-state power should include the manufacturer's derating curve.
• Use finite inputs in the displayed units and preserve more precision than the final presentation requires. Independently verify safety-critical, financial, compliance, or production decisions.

Check the result against the current datasheet and worst-case operating corners, then verify the circuit or measurement with simulation and bench testing where failure matters.

• Coax C Per Meter

  Compute coaxial cable capacitance per meter as 24.1 x er / ln(d_outer/d_inner) with diameters in matching units.

• Coax L Per Meter

  Compute coaxial cable inductance per meter as 200 x ln(d_outer/d_inner) nH/m from the loop inductance mu_0/2pi x ln(b/a).

• PCB Via Current from Thermal Model

  Estimate via current from an allowed temperature rise and user-supplied effective thermal resistance using I=sqrt(ΔT/(R_electrical·R_thermal)). Barrel electrical resistance uses copper resistivity, length, and plated annulus area. This simplified lumped model requires board-specific thermal resistance.