The CALIBRATION VOID IF SEAL BROKEN label is placed over readily accessible
adjustments to prevent tampering by the user when such tampering could affect the calibration.
The MEASURE system is designed to standardize the recall and scheduling of test, measurement,
and diagnostic equipment into calibration facilities and for the documentation of actions performed by the
MAINTENANCE is work done to correct, reduce, or counteract wear and damage to equipment.
PREVENTIVE MAINTENANCE consists of checks to determine weather equipment is
functioning properly. It also consists of visual inspections of cabling and equipment for damage and to
determine if lubrication is needed.
CORRECTIVE MAINTENANCE is used to isolate troubles by means of test techniques and
practices that realign or readjust equipment or otherwise bring the equipment back up to proper
SENSITIVITY of the voltmeter is always given on the voltage charts for a particular piece of
equipment. You should always use a voltmeter of similar sensitivity to the equipment to diminish the
effects of circuit loading.
CURRENT MEASUREMENTS are not often taken in the course of testing because the ammeter
(or other current measuring device) must become an actual part of the equipment being tested. The circuit
must be opened for necessary connection of the meter. Usually you can use a voltage measurement to
calculate the circuit current by applying Ohms law.
You should observe the following PRECAUTIONS when using an ohmmeter:
1. The circuit being tested must be completely de-energized.
2. Any circuit components which can be damaged by ohmmeter current must be removed before any
measurement is made.
The WHEATSTONE BRIDGE is used for precise measurement of resistance.