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Syscal Junior - Switch 72


Syscal Junior Switch 48 | Switch Plus 3D Resistivity Imaging Option | Syscal Junior Console

Syscal Junior resistivity meterResistivity Imaging For Environmental Applications
  • Compact yet powerful
  • 400 V - 100 W - 1.2 A
  • Automatic ranging
  • Automatic switching

SYSCAL Jr Switch-72 is a new all-in-one multinode resistivity imaging system. It features an internal switching board for 72 electrodes and an internal 100 W power source. The output current is automatically adjusted (automatic ranging) to optimise the input voltage values and ensure the best measurement quality. The system is designed to automatically perform pre-defined sets of resistivity measurements with roll-along capability. Four strings of cable with 18 electrode take-out each are connected on the back of the resistivity meter. Made of heavy duty seismic cable, these strings are available with standard 5 or 10 m electrode spacings. Customized cables may also assembled for special arrays or non-standard applications.

Compact, easy-to-use and field proof, the SYSCAL Jr Switch-72 measures both resistivity and chargeability (IP). It is ideal for environmental and civil engineering applications such as pollution monitoring and mapping, salinity control, depth-to-rock determination and weathered bedrock mapping. It can also be used for shallow groundwater exploration (depth and thickness of aquifers).

With the SYSCAL Jr Switch-72 resistivity surveys can be performed very efficiently with one operator only.

(Please, Click on the Picture for a Larger version)

  • Aim: imaging the underground geological structures through surface electrical measurements
  • Principle: transmitting a current I through two electrodes and measuring a voltage V with two other electrodes
  • Apparent resistivity: p = K*V/I, K depending on the electrode separation
  • Resistivity pseudo-section: contoured plot of the apparent resistivity data, using the electrode distance as a pseudo-depth parameter
  • True resistivity section: contoured plot of the resistivity distribution obtained through the inversion of the measured data (using a non linear parameter fitting scheme)
  • Applications: environmental studies, groundwater investigation, civil engineering, archaeology...

Preset arrays (Wenner, dipole,) or customized arrays are uploaded through the user-friendly ELECTRE (version 2) PC software. The roll-along capability is implemented.


  • Automatic SP compensation including linear drift
    Digital stacking for noise reduction
    Standard deviation computation
    Noise may be monitored before injection


  • RES2DINV or RESIX-2DI (PC), for pseudo-section inversion to true resistivity (and IP) 2D section.
    RES3DINV (PC), for inversion to true resistivity (and IP) 3D data


  • Automatic ranging (microprocessor controlled)
  • Intensity: up to 1200 mA
  • Voltage: up to 400V (800V peak to peak)
  • Power: up to 100 W
  • Selectable cycle time of 0.5 , 1 or 2 s, programmable from 0.25 to 10 sec.
  • Current measurement precision: 0,5% typical.


  • Measuring process: automatic ranging and calibration
  • Input impedance : 20 MW minimum.
  • Input voltage protection up to 1000V, range from 5 V to +5 V.
  • Power line rejection
  • Voltage measurement precision: 0.5% typical
  • Noise reduction: continuous stacking selectable from 1 to 255 stacks.
  • SP compensation through automatic linear drift correction.
  • Resistivity accuracy: 0,5% typical
  • Induced polarization (chargeability) measured over four predefined windows.
  • Chargeability accuracy: 1% of measured value for input voltage higher than 10 mV.


  • Weather proof
  • Shock resistant fiber-glass case
  • Operating temperature: -20 to +70 C
  • Dimensions: 31 x 23 x 35 cm. Weight: 11.5 kg
  • Internal memory for 2700 readings
  • Power supply: two internal rechargeable 12V, 7 Ah battery ; optional external 12V backup car battery for transmitter power
  • Autonomy with internal battery: several thousands of readings
  • 18 take-outs cable string weight: 15 kg each for 5m spacing