Chapter 6 - Instrumentation

Question 1

Which 2 resistance values must be kept in mind to correctly measure the voltage difference between a pipeline and a reference electrode?

Answer 1

• External circuit resistance of reference electrode.

- Input impedance of voltmeter.

Question 2

Most conventional multimeters currently produced have an internal impedance of ……..

Answer 2

10 million ohms

Question 3

This instrument uses 4 pins to obtain a reading using the “Wenner Method” to measure the soil.

Answer 3

soil resistivity meter

Question 4

this instrument can store thousands of pipe-to-soil readings including text comments

Answer 4

Data recorder

Question 5

this device can accurately measure wall thickness using sound waves

Answer 5

ultrasonic thickness gage

Question 6

this equipment impresses an electrical signal onto the target line to permit a hand-held receiver to detect the location.

Answer 6

pipe and cable locator

Question 7

this device uses amplifying coils positioned around a pipe or cable to measure AC or DC current flow

Answer 7

ammeter clamps

Question 8

this equipment finds pinholes and small coating defects by impressing an electrical voltage across the coating that is detected by an electrode.

Answer 8

holiday detector

Question 9

which reference electrode should be used in soils for cathodic protection but not in high chloride environments?

Answer 9

copper-copper sulfate

Question 10

which of the reference electrodes is NOT used in cathodic protection

• copper copper sulfate
• silver-silver sulfate
• antimony
• zinc

Answer 10

antimony