Here’s what the HEW-200 will do for you:

  • 500 watt Induced Polarization for sulfide prospecting
  • Lightweight (38 pounds/17.2 Kg)
  • Transmitter – Receiver in one package
  • Two to Three man operation, depending on configuration
  • Impressed EMF integration as well as induced polarization integration
  • Remote operation using very high power supplies for deep exploration
  • Low pass signal filtering
  • Positive phase locking
  • No external generators required (self-contained rechargeable power supply)
  • Versatile configurations for ground level surveying, bore hole logging, test cell analysis, and more
  • High receiver input impedance (1 x 10^6 ohms)
  • Weatherproof construction
  • Simple operation
  • Low initial investment
  • Dozens of units sold and used worldwide


The HEW 200 – Induced Polarization Prospecting Unit, is the most versatile and portable unit available. It is a light weight, compact, ruggedly built unit and extremely convenient for transport and operation. The unit is equipped with rechargeable batteries which make it unnecessary to transport a generator.

The HEW 200 uses the time domain principle with simplicity of operation and maintenance as the prime consideration in design.

Several important features are incorporated in the receiver such as:

  • Self potential measurements.
  • Impressed EMF voltage phase locked to transmitter, integrated and stored automatically to reduce resistivity errors caused by current electrode polarization.
  • The same for the residual IP measurements.
  • Elimination of self potential errors by automatic reverse cycling of transmitter current.
  • Low pass filtering to minimize AC or sporadic electrical noise.

Batteries are easily charged overnight at any standard electrical outlet or from storage batteries. The battery power supply is sufficient for one to several days’ survey operations without recharging, depending on the use. Internal batteries can be removed and the unit can be operated with external batteries with minor modifications.

Induced polarization and resistivity logs may easily be made in diamond drill holes. Sample cores, rock chips, or other material can be tested in the field for polarization response using a simple test cell.

Two pulse time periods are available, two second or four second, and may be used to some degree to differentiate between primary sulfide polarization and secondary membrane polarization.

This basic induced polarization unit, plus several non-polarizing disposable electrodes and a few short lengths of wire, is all that is needed to conduct a two-man mineral survey.


Receiver-Transmitter Package

Dimensions 15″ X 13″ X 10″ (38 X 33 X 25 cm) -approximately.
Weight 38 pounds (17.2 Kg)

Receiver Power Supply:

  • 4 ea. #216 or #222 ER Transistor radio batteries
  • 1 ea. AA Alkaline battery for reference voltage

Transmitter Power Supply:

  • 30 Volt rechargeable battery 5-RF 680 Central Lab


  • Common mode rejection 100dB (DC-60Hz)
  • Low pass filter input 100dB 60 Hz
  • Input impedance 1 X 106 ohms
  • Operation temperature: -20 C to + 75 C
  • Taught Band IP and current meters
  • Polarity automatically read on meter dial
  • Three input combinations
  • Sealed switches and panel for wet climate operation (internal dessicant included)


  • 24-30 Volt DC-DC transistorized converter
  • Power output 500 watts maximum
  • Two or four second pulse interval timer
  • Automatic reverse current cycling
  • Operating temperature: -20 C to + 75 C
  • Sealed switches and panel for wet climates (internal dessicant included)
  • Sealed meter for very humid or wet climates

Auxiliary Equipment:

Non-Metallic Reels

  • Phenolic construction with communicator for very low electrical leakage and safety
  • 3,000 feet (915 m) capacity
  • 12″ X 13″ X 7.5″ (31 X 33 X 19 cm)

Non-Polarizing Electrodes

  • 2″ diameter X 3″ long (5.1 cm diameter X 7.6 cm long)
  • Porous base
  • Copper sulfate type
  • See-through acrylic construction to check liquid level