FL2 vs FL3T Shunt: Key Feature Differences

author: Milliohm Electronics

2026-03-13

I. Electrical Parameters

Series	Rated Current	Voltage Drop	Tolerance	T.C.R（ppm/℃）
HoFL2	300A	75mV	0.1%~5%	≤50
HoFL3	300A	75mV	0.1%~5%	≤50

II. Material and Structure Comparison

① Material Comparison :

FL2 series products: The electrode material is national standard brass, and the resistive element is national standard precision manganese copper;
FL3 series products: The electrode material is national standard copper, and the resistive element is national standard precision alloy.

② Welding Process

The welding process between the FL2 electrode and the resistive element is conventional high-frequency soldering, as shown in Figure 1 (left);

The welding process between the FL3T electrode and the resistive element is electron beam soldering, as shown in Figure 1 (right).

③ Comparison of Sampling Methods

The FL2 sampling point is commonly installed using screws.
The FL3T sampling methods commonly include pin-type, crimp-type, and solder-type (as shown in the image below, pin-type, crimp-type, and solder-type, respectively). Additionally, the FL3T can be mounted on a PCB sampling module, facilitating improved product integration. It can also be used with a high thermal conductivity substrate or heat dissipation material to reduce temperature rise and its impact on accuracy.

④ Package Size Comparison

⑤ Comparison of Installation Methods

FL2 Package type: Fixed installation, Mostly in busbar form;

FL3 package type: fixed installation, the same installation method as FL2 and compatible with FL2 mounting dimensions. (Note: There are directional requirements for installation; the wire terminals must be on the crimp nut side.)

III. Summary

Based on a comparison of the electrical parameters, package size, manufacturing process, and materials of FL2 and FL3T, the following conclusions are drawn:

① FL3T has advantages over FL2 in welding process, mainly due to the more orderly molecular structure arrangement, less heat generation, and lower temperature rise in electron beam welding, resulting in better performance in terms of workpiece thermal stress and micro-deformation;
② FL3T electrodes use national standard purple copper material, which has better heat dissipation than the brass electrodes used in FL2;
③ FL3T has a smaller volume (using less material) than FL2 for the same power, resulting in lower cost.
④ FL3T has a simpler package structure, resulting in lower parasitic inductance and better performance in high-frequency and AC applications.

The FL3 has advantages in terms of product performance, quality, temperature, and cost.

HoFL2 Series purchasing link : HoFL3T Series purchasing link :