Compensation Methods of Effect of Lead Wire Extension

If the lead wire or cable is extended with the quarter-bridge or half-bridge system, additional resistance is initiated in series to the strain gage, thereby decreasing the apparent gage factor. For example, if a 10 m long lead wire with 0.3 mm2 conductors is used, the gage factor decreases by 1%. In the case of the full-bridge system (transducer), the extension decreases the excitation voltage too. In these cases, the real strain ε is obtained by the following equation. (Supposing the gage factor Ks is 2.00):

Lead wire resistance values

Cross Section
(mm 2 ) 		Number of Standards/Wire Diam.(mm) Reciprocating Resistance per 10 m(Ω) Remarks
0.08
0.11
0.3
0.5 		7/Φ0.12
10/Φ0.12
12/Φ0.18
20/Φ0.18 		4.4
3.2
1.2
0.7 		L-6
L-9
L-2
L-5