Silver Plated Tungsten and Tungsten-Rhenium Probe Needles

Description

Material DC Resistivity
Note: The resistance values were calculated using Ohm’s Law for parallel resistors. There was a statistically significant correlation between the “theoretical values” in the table and direct measurements from the various probe needle diameters.
Tungsten
Needles

Tungsten-Rhenium Needles

Plated Nickel
Needles

Plated Silver
Needles
5.5 to 5.9 µΩ−cm

9.2 to 10.1 µΩ−cm

7 to 40 µΩ−cm

1.6 to 3.2 µΩ−cm

DC Resistance and Current Carrying Capacity
Note: The current carrying capacity was determined based on the power dissipated by heat.
Plated Probe
(200-µin thickness
on a 2.0 inch long
probe needle)

Nominal Nickel
Plated Probe
Resistance
(mΩ)

Nominal Silver
Plated Probe
Resistance
(mΩ)

% Resistance
Reduction

% Ampacity
Increase
Tungsten
5
6
7

229.4
158.9
114.8

148.7
109.6
83.4

35.2
30.9
27.3

19.5
16.9
14.8
Tungsten-Rhenium
5
6
7

376.1
260.0
188.7

198.9
149.9
116.6

47.1
42.3
38.2

27.3
24.1
21.4