ASE Practice Test (A6: Electrical/Electronic Systems)

Question 1

To check the continuity of wires that carry digital signals, which of the following tools can be used?

Accepted Answer

Logic probe

Answer

A logic probe is specifically designed to detect and display the presence of digital signals (high, low, or pulsing states) in electronic circuits without significantly loading the circuit. While a voltmeter can measure voltage, it is less effective for quickly interpreting the dynamic states or fast pulses characteristic of digital signals. A megger meter measures insulation resistance, and an analog meter is less precise for digital signals.

Question 2

When using the passenger side control switch, the passenger side power window works properly, but when using the driver's side master control switch, the window only works in the DOWN position. Which of these possibly be the source of the problem?

Accepted Answer

An open circuit in the driver’s side master control switch

Answer

If the passenger window works correctly from its own switch but only works in the DOWN position from the driver's master control switch, it indicates an issue within the master switch itself. Specifically, the 'UP' contact or circuit for the passenger window within the driver's master switch is likely open or faulty, preventing the 'UP' signal from being sent. The passenger switch's full functionality confirms the motor and associated wiring are otherwise fine.

Question 3

Which of the following statements regarding a series circuit is correct?

Accepted Answer

Highest resistance contains the highest voltage drop

Answer

In a series circuit, the current flowing through all components is the same. According to Ohm's Law (V=IR), the voltage drop across a component is directly proportional to its resistance. Therefore, the component with the highest resistance in a series circuit will experience the largest voltage drop across it.

Question 4

A fully charged 12 volt battery should indicate how much voltage on the open circuit voltage (OCV) test when using a DMM (Digital Multimeter).

Accepted Answer

12.6 volts

Answer

A fully charged 12-volt lead-acid battery consists of six individual cells, with each cell producing approximately 2.1 volts when fully charged. Therefore, a fully charged 12-volt battery should indicate around 12.6 volts (6 cells x 2.1 V/cell) when measured with a Digital Multimeter (DMM) during an open-circuit voltage (OCV) test.

Question 5

Technician X says that if a fusible link in the alternator charging circuit is replaced with system sized wire, the circuit will be unprotected. Technician Y says that if a fusible link in the alternator charging circuit is replaced with system sized wire, the battery will overcharge. Who is right?

Accepted Answer

X only

Answer

A fusible link is a safety device designed to melt and open a circuit when excessive current flows, protecting other components. If a fusible link is replaced with a standard wire of the same gauge, it loses its protective function. This 'system sized wire' will not melt under overcurrent conditions, leaving the circuit unprotected and vulnerable to damage from excessive current. Technician Y's statement about overcharging is incorrect, as fusible links are for overcurrent protection, not voltage regulation.