An automotive technician needs to measure the operational current drawn by a 12-volt DC ra… — Armed Services Vocational Aptitude Battery (ASVAB)

An automotive technician needs to measure the operational current drawn by a 12-volt DC radiator cooling fan known to consume roughly $4.5\text{ A}$ . How should the digital multimeter be configured and connected to perform this measurement accurately and safely?

A
Connect the black lead to COM, red lead to $\text{V}/\Omega$ , set the dial to $20\text{ V DC}$ , and connect the test probes in parallel across the fan terminals.
Connect the black lead to COM, red lead to the $10\text{ A}$ jack, set the dial to DC current, and connect the meter in series with the fan circuit.Cevap
C
Connect the black lead to COM, red lead to the $\text{mA}$ jack, set the dial to $200\text{ mA DC}$ , and connect the meter in series with the fan circuit.
D
Connect the black lead to COM, red lead to the $10\text{ A}$ jack, set the dial to AC current, and connect the test probes in parallel across the fan terminals.

Cevap

Connect the black lead to COM, the red lead to the

10\text{ A}

jack, set the selector to DC current, and place the meter in series with the fan circuit.

Measuring electrical current requires opening the circuit and placing the ammeter in series with the load. Because the anticipated current is

4.5\text{ A}

, the black lead must go to COM, the red lead to the high-current (

10\text{ A}

) input jack, and the selector set to direct current (DC).

Adım Adım Çözüm

Determine the measurement mode and circuit connection type.

Current measurement requires breaking the circuit and inserting the meter in series so that all electrons pass through the meter.

Ammeters have near-zero internal resistance and must be in series with the load to measure flow without creating a parallel short circuit.

Select the proper current type and magnitude range.

Automotive systems supply direct current (DC), and

4.5\text{ A}

exceeds standard milliamp jack limits (typically

200\text{ mA}

400\text{ mA}

Selecting the

10\text{ A}

input prevents blowing the meter's low-current protection fuse.

Configure the multimeter probe jacks and rotary dial.

Insert the black probe into the COM port, the red probe into the

10\text{ A}

port, and turn the dial to the DC Amperes (A DC / DCA) setting.

This establishes the correct low-impedance measurement path for high-current DC evaluation.

Anahtar Kavram

Digital Multimeter Current Measurement Configuration and Lead Placement

Tahmini Süre:1m 0s

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