breakage (version 1.1-1)

resist.total: Calculate overall pipette tip resistance

Description

Calculates the resistance of a pipette tip, as the sum of its internal conical resistance and external access resistance. Pipette geometry is specified in terms of length, tip radius and half-cone angle.

Usage

resist.total(r, l, theta, rho = 51)

Arguments

r

Pipette tip (inner) radius, in microns.

l

Pipette length, in microns. Note that resistance contribution falls of markedly away from the tip, so the exact length may not be crucially important.

theta

Pipette internal half-cone angle, in radians.

rho

Resistivity of the pipette filler medium, in ohm centimetres. The default value of 51 ohm cm corresponds to a 150 mM solution of KCl.

Value

See Also

resist.access, resist.cone, resist.breakage

Examples

# total resistance for a 30 micron long pipette tip with a half-cone angle of 4 degrees
# and a tip radius of 50nm, with a filler/bath resistivity of 64 ohm cm
# converting result from ohms to megohms for readability
resist.total(r=0.05, l=30, theta=4*pi/180, rho=64) * 1e-6