The extensometer MFA 20 is suitable for determining the yield point and uniform deformation for test samples above 4 mm diameter and 15 mm width. The measurement accuracy corresponds to the accuracy class 0.5 of the EN ISO 9513. Because of its extremely robust design the instrument is suited for heavy duty service such as testing of construction steel and rough samples with scale etc.
The gauge length may be adjusted very quickly and precisely from 50 to 200 mm in 10 (5) mm-steps by shifting the lower knife edge holder.
The clamping may be made without any problems with one hand. The parallel positioning of the MFA 20 in respect to the axis of round samples is guaranteed by centering two double knife edges

TECHNICAL DATA OF THE MFA 20 EXTENSOMETER
Accuracy class EN ISO 9513 0.5
Measuring principle Strain gauge full bridge
Travel for tensile test +20 mm
Measuring path tolerance 50 μm
Measuring path tolerance 0,25%
Linearity error including hysteresis 0.2 %
Indication error (rel.) * 0.5 %
Indication error * 1.5 μm
Error in gauge length 0,5 %
Activating force 150 cN
Sensitivity 2 mV/V
Rated resistance of bridge 350 Ohm
Standard gauge length (Lo) 50 to 100 mm (steps of 10 (5) mm)
Option gauge length (Lo) From 40 mm
Accessory gauge length (Lo) Up to 200mm (steps of 10 (5) mm)
Weight ca. 480 g

• Metals and Alloys

The measurement accuracy corresponds to accuracy class 0.5 according to EN ISO 9513.