Determination of the Resistance per Unit Length (ohm/cm) of Swab Handles

Test Method 16Test Method 16

Determination of the Resistance per Unit Length (ohm/cm) of Swab Handles

Swabs can transport charge and generate static charge due to contact with other surfaces. Such charges can subsequently lead to electrostatic discharge (ESD) that can damage products or equipment.

"Swabs can transport charge and generate static charge due to contact with other surfaces.

Such charges can subsequently lead to electrostatic discharge (ESD) that can damageproducts or equipment. Although swab handle resistance (see below) is not the only factordetermining the charge accumulated by the swab or placed on other surfaces by the swab,it is a major factor. Lower resistance leads to less charge accumulation. Very low resistance can lead to excessive rates of charge transfer (current).

For a simple resistor, resistance is often measured by applying a voltage difference (V) to theleads, measuring the current (I) and inferring the resistance as R=V/I, once a steady state has been reached or after a fixed time. Resistance will depend on the geometry of the resistor. For a cylinder, it is R=(rho.v) L /A, where (rho.v) is the volume resistivity, L is the length andA is the cross-sectional area (assuming a negligible contribution from surface current). Resistance measurements for some high-resistance..."