Establishing a Field Indicator Reference Standard
Checking the In Use Field Indicators. (See Figure 1-9b.)
Place a small bar magnet (approximately 1 by 1/2 inch) vertically near the bottom of an 8 1/2- by 11-
inch sheet of paper and trace around the magnet with a marker. (It does not matter which pole of the
magnet is up.)
Place the field indicator reference standard on a sheet of paper with the bottom of the indicator above
and in line with one pole of the magnet.