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LE-xD 1Hz Seismometer Sensors
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The LE-xD 1 Hz Models

These are the workhorses of the scientific product line.  Originally available in a blue rectangular housing (known for a long time as the "LE-3D classic", now out of production), hundreds of these sensors are in daily duty all over the world.  The current model (shown below) comes in a cylindrical stainless steel housing and is called LE-3Dlite.  Additionally, single component versions for vertical or horizontal use are available, aptly named LE-1D/V and LE-1D/H.

Users are attracted by these unique features that set these sensors miles apart from their mechanical predecessors:

  • Extremely compact and lightweight
  • Rugged
  • Sheer simplicity; true plug-and play operation
  • All sensors calibrated to identical output voltages; no need to keep records of which sensor has been connected to which datalogger
  • Low noise, low power (typically 3 mA per component @ 12 V DC)
  • Dynamic range > 120 dB
  • Comparatively insensitive to improper leveling
  • No mass lock, mass center, control box, or other contraption required; can be transported in any orientation
  • Proven long-term stability; well over ten years of field experience
Technical Details

The following table shows the relevant technical parameters for both the single and the three component versions of the 1 Hz seismometers:

  LE-1D/H and LE-1D/V LE-3Dlite
Power Supply 10...16V DC, unstabilised 10...16V DC, unstabilised
Output Voltage 400 V/m/s, precisely adjusted 400 V/m/s, precisely adjusted on all components
Damping 0.707 critical (internal damping; independent of datalogger input resistance) 0.707 critical (internal damping; independent of datalogger input resistance)
Dimensions 85 mm diameter
55 mm height
95 mm diameter
65 mm height
Weight, including 1.5 m cable and Cannon KPT connector) 1.1 kg 1.8 kg
Temperature range -15...+35C -15...+35C
Optional temperature range (specify when ordering) 0...+50C 0...+50C
Housing Stainless steel, matted surface, splash proof, with level adjustment feet and water bubble level control Stainless steel, matted surface, splash proof, with level adjustment feet and water bubble level control
Eigenfrequency 1 Hz 1 Hz
Upper corner frequency > 80 Hz > 80 Hz
RMS noise at 1 Hz < 3 nm/s < 3nm/s

The single component seismometer must be ordered for vertical (/V) or horizontal (/H) operation; the two versions are not convertible or retrofittable.

The "upper corner frequency" row denotes the frequency up to which the sensors have been tested on a shake table.  Users should be aware that there is an inherent low pass filter in the sensor's circuitry which will gradually damp away frequencies higher than the upper corner frequency.