Model CPV-4 Digital Cathodic Protection by Tinker & Rasor

All-in-One Device for Cathodic Protection Potential Measurements

The Tinker & Rasor Model CPV-4 Cathodic Protection Voltmeter is a revolutionary instrument for measuring DC structure to earth potentials of various buried or submerged metallic objects. Powered by an ordinary 9-volt battery, the Model CPV-4 gives an immediate reading in large ½ inch (12.7mm.) liquid crystal display numerals.

The large scale integrated circuit has a built-in filter to reject AC interference. Input resistance of 11 megohms (11 million ohms) yields potentiometer quality voltage readings, and digital readout eliminates interpolation of voltages. This small, lightweight instrument needs no warm-up time, is insensitive to temperature, and can be read in direct sunlight. Low current CMOS circuitry assures long battery life, and the die-cast metal case makes the CPV- 4 a durable instrument for the field.

Study the features and specs and see how they combine to make the Tinker & Rasor CPV- 4 the most accurate and reliable cathodic protection voltmeter ever afforded.


  • Die-cast aluminum case
  • Baked enamel finish
  • 9-Volt transistor battery, long life
  • Liquid crystal display digital meter
  • Integrated circuites
  • Two heavy-duty coil cables with /clamp & banana plugs
  • No warm-up time



+0.1% + last digit


Dual scale: 0 to 1.999 V


9 Volt transistor type


4 5/8" x 3 5/8" x 2 3/16" (117 x 92 x 59 mm)


16 oz (454 g)

Shipping weight

3 1/2 lbs (1.59 kg)

Ordering Information

Model CPV-4 Voltmeter complete consists of:

  • A - Instrument.
  • B - Copper-copper sulfate half cell electrode (Model 6A). Model 6B, 8A, or 8B may be substituted.
  • C - Two heavy-duty 6 ft coiled cables with clamps.
  • Carrying case L-13" x W-7" x H- 4 3/4" (330 x 178 x 121 mm).
  • Instruction Manual with parts list (not shown).