Spring Force

Probe Selection

QA Technology offers many combinations of probes. You can build your probe by selecting the tube style, tip style and spring force for your specific application.

If you have questions at any time during the process, contact us at (603) 926-0348.

Begin building your part number.

NOTE: P has already been selected for you as the default tube material.

Letter	Material	Average Resistance			Current Rating¹ SS @ 204°C
P	Nickel silver/ID precious metal clad	< 75 milliohms			3.6 Amps

Select your tip style. Standard material is heat-treated BeCu/plated gold over nickel.
Choose

for steel plungers, if available.
Use the drop-down menu at right to filter your choices by target type.

Select your spring force.

Letter	Spring Force	Preload	@ 0.317 [8.05] Stroke	Material	Cycle Life @ 0.317 [8.05] Stroke
S	Standard	0.7 [20g/0.19N]	4.0 [113g/1.11N]	SS	50,000
H³	High	1.8 [51g/0.50N]	6.0 [170g/1.67N]	SS	50,000

Select your option (if required).

Letter	Description
D	Decreased stroke is 0.250 [6.35]. Must select from 039-25 Series spring forces with this option.
N	No probe lubrication. Removing probe lubrication greatly reduces cycle life and should only be used in applications requiring operating temperatures below -45°C or above 120°C.
	Heat treated steel/plated gold over nickel (see tip styles for availability)

You may add your Part Number to your Order.

¹Current Rating is affected by spring material and lubrication choice. MW springs and lubrication both have a 120°C operating temperature limit. Use SS springs with no lubrication (-N) for testing up to 204°C. Before using probes near these limits, please refer to Current Carrying Capacity and Operating Temperature Application Notes.

²Maximum plunger OD should be used to calculate minimum guide plate clearance holes.

³ 0.350 [8.89] max stroke for H spring

All specifications subject to change without notice. All dimensions are in [mm]. All spring forces are oz [gm/newtons]. US Patent No. 4,885,533