Lesson 2: General Use Test Instruments

AC voltage is voltage in a circuit that reverses its direction of flow at regular intervals, and is stated and measured as peak, average, or ? value. a. MIN/MAX b. regular c. rms d. standard

c. RMS

Many test instruments include a ? in the current-measuring circuit to prevent damage caused by excessive current. a. bypass b. circuit breaker c. fuse d. relay

c. fuse

A(n) ? is a test meter that measures resistance, the opposition to the flow of electrons in a circuit. a. ammeter b. chronometer c. ohmmeter d. voltmeter

c. ohmmeter

In-line ammeters require the circuit to be ? so the ammeter can be inserted into the circuit to acquire a reading. a. closed b. low voltage c. opened d. parallel

c. opened

An ohmmeter is used to measure the ? . a. amperage b. direction of voltage flow c. resistance d. voltage

c. resistance

? leakage current is current that flows from areas on conductors where insulation has been removed to allow electrical connections. a. Capacitive b. Conductive c. Surface d. Terminal

c. surface

One advantage of voltage testers is that they have a lower impedance (resistance) and draw more current than voltage indicators, which allows them to be used for testing ? . a. insulation b. job order motors c. job order wiring d. GFCIs

d. GFCIs

Voltage measurements using the ? on a digital multimeter are useful in identifying low voltage conditions. a. analog scale b. bar graph c. diode test mode d. MIN/MAX mode

d. MIN/MAX mode

A clamp-on ammeter is a test instrument that measures current in a circuit by measuring the strength of the ? around a single conductor. a. ampacity b. electromotive force c. inductive reactance d. magnetic field

d. magnetic field

AC current is current in a circuit that flows in one direction only.

False

Most analog multimeters do not have calibrated scales that correspond to the different selector switch settings.

False

The higher the resistance in a circuit, the higher the current flow through the circuit.

False

Voltage indicators only indicate that voltage and current are present; they do not indicate the actual voltage.

False

A clamp-on ammeter is typically used to measure current in a circuit with over one ampere of current.

True

A closed switch that is operating properly has continuity.

True

A megohmmeter is a high-resistance ohmmeter used to measure insulation deterioration on various wires by measuring high-resistance values during high voltage test conditions.

True

A permanent test instrument is a device that is installed in a process, or at a bench, to continually measure and display quantities.

True

A portable test instrument is used to take real-time (momentary) measurements.

True

A voltage indicator needs only to be near a voltage source to indicate the presence of voltage.

True

Measuring current is useful because only current can be used to determine how much a circuit is loaded (working).

True

When using an ohmmeter, the resistance of all components connected in parallel with the component being tested affects, and typically lowers, the resistance reading.

True

When voltage measurements are different from what is expected, the voltage measurement is most likely to be lower than normal.

True

Current is measured in ? . a. amperes b. ohms c. volts d. watts

a. amperes

When a 3-phase current unbalance exceeds ? , a test for voltage unbalance should be performed. a. 3% b. 10% c. 20% d. 30%

b. 10%

Most digital multimeter displays include a(n) ? to show changes and trends in a circuit. a. analog scale b. bar graph c. diode test mode d. MIN MAX mode

b. bar graph

One problem with small 3-phase voltage imbalances is that they cause high ? imbalances. a. core b. current c. power d. resistance

b. current

The ? value of a sine wave is the maximum instantaneous value of either the positive or negative values in the sine wave. a. average b. peak c. positive d. rms

b. peak