HOOK-ON TYPE VOLTAMMETER

1-47 Q57. What is the reason for having a mirror on the scale of a multimeter? Q58. How is the mirror on a multimeter used? Q59. List the 11 safety precautions for multimeters. OTHER METERS In addition to the ammeter, voltmeter, ohmmeter, and multimeter, you will probably use many other types of measuring devices. Many of those measuring devices (test equipment) are discussed later in this training series. The following brief discussion of a few additional meters will introduce you to some of common measuring devices you will use in working on electrical and electronic circuits. HOOK-ON TYPE VOLTAMMETER The hook-on ac ammeter consists essentially of a current transformer with a split core and a rectifier- type instrument connected to the secondary. The primary of the current transformer is the conductor through which the current to be measured flows. The split core permits the instrument to be "hooked on" the conductor without disconnecting it. Therefore, the current flowing through the conductor may be measured safely and easily, as shown in figure 1-43. Figure 1-43.—A hook-on type voltammeter. The instrument is usually constructed so that voltages also may be measured. However, in order to read voltage, the meter switch must be set to VOLTS, and leads must be connected from the voltage terminals on the meter to terminals across which the voltage is to be measured.