High Elongation Extensometers – Model 3800

Designed for rubber, elastomer and high-elongation plastics testing for strains from 100%-2000%ε. Their unique design allows testing to failure and minimizes interaction with the sample.

Epsilon extensometers are COMPATIBLE WITH VIRTUALLY EVERY BRAND OF TEST EQUIPMENT and can be supplied with the correct connector to plug in directly, or supplied with a separate conditioner and amplifier.

to the materials testing community, you know we will be there to stand behind our products when your critical application requires it.

38 EXTENSOMETER MODELS are available in many thousands of variations. Our focus on helping customers has led to the development of models to cover nearly any test method.

The main body of this unique extensometer remains stationary during testing, held in position by the adjustable magnetic base included. Only the very light, small traveling heads move as the sample elongates during a test. These attach to the sample with small spring clips. Each head pulls a cord out from the extensometer as the head moves.

These models use low friction potentiometers and have a range of factory-selectable outputs. The extensometer is driven by an excitation voltage and has output proportional to the input. They are provided with outputs that mimic strain gaged devices (2-4 mV/V). The Model 3800 can be used with virtually any signal conditioning electronics designed for strain gaged sensors. For systems lacking the required electronics, Epsilon can provide a variety of solutions for signal conditioning.

Download Data Sheet

  • May be left on through specimen failure.
  • Applicable for testing to ASTM D412.
  • The main body is stationary with only the lightweight traveling heads moving.
  • Comes with an adjustable magnetic base for easy mounting.
  • Large measuring range to 500 mm (20 inches).
  • Includes the Epsilon Shunt Calibration System for on-site electrical calibration.
  • Includes high quality foam lined case.
  • Low cost strain measurement for testing high-elongation materials (>100%ε).

Download Data Sheet

Excitation: 5 to 10 VDC recommended, 12 VDC or VAC max.

Output: 2 to 4 mV/V, nominal; select at time of order

Accuracy: ±1 mm (±0.040 inches)

Resolution: 0.2 mm (0.008 inches)

Temperature Range: -40 °C to 100 °C (-40 °F to 210 °F)

Cable: Integral, ultra-flexible cable, 2.5 m (8 ft) standard

Operating Force: <200 grams typical per head




Download Data Sheet

  • Adapter kits to change gauge lengths.
  • Connectors to interface to nearly any brand of test equipment.

Download Data Sheet

Product Videos

Demonstration: tension test of a rubber material per ASTM D412 using the Model 3800 extensometer.
Setup instructions for the Model 3800 extensometer.

Ordering Information

Click table options to configure

Gauge Length i
mm or inches #
20.0 mm -020M 020M
25.0 mm -025M 025M
50.0 mm -050M 050M
1.000 in -0100 0100
2.000 in -0200 0200
Measuring Range i
extension #
+250 mm -250M 250M
+500 mm -500M 500M
+10.0″ -100T 100T
+20.0″ -200T 200T
Model Number:  3800_ _ _ __ _ _ _
Model Number:
3800_ _ _ __ _ _ _
Model 3800 Available Versions: ANY combination of measuring ranges and gauge length listed above is available. Available in intermediate and larger gauge lengths on special order.

Example: 3800-0100-100T: 1.0 inch gauge length, +10 inches measuring range (+1000% strain), temperature range of -40 °F to 210 °F


If your unit is in need of service, calibration or repair, initiate the RMA process with us and we will be happy to assist.

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Our 2022 Extensometer Catalog, Version 110 is now available! Not finding something you’re looking for? Ask us about a custom quote.