ASE B5 Mechanical/Electrical Exam: Questions &
Answers
How are voltage tests measured? - ANSWER:Voltage tests are measured with the test leads of the DMM
in parallel to the component or circuit being tested.
How do you test applied voltage? - ANSWER:1. In testing applied voltage, the negative or black test lead
of the DMM is connected to a battery or chassis ground
2. The positive red lead is then probed near the power source (e.g. a switch or fuse) to determine if the
circuit is receiving the proper voltage.
What is a handy feature of a DMM? - ANSWER:Polarity is not important.
2. If the leads are reversed. the display will simply include a minus sign in front of the reading.
How are circuit voltages tested. - ANSWER:Take a positive test probe and go from one circuit's power
source to the next.
Generally, the applied voltages _______________. - ANSWER:Should be the same.
What is recommended when selecting a DMM to use for testing electronics circuits? - ANSWER:1. It is
recommended that it have a 10 megohm or higher impedance.
2.This is necessary to limit the effect the unit might have on accuracy when testing low current flow
circuits.
3.The lamp in the test light will draw too much current and this can damage the circuit integrity.
What should be done if it is necessary to test for voltage in an energized circuit - ANSWER:1. A
convenient way to do this is with a black-probe tool, also know as a "spoon," at various connectors in a
particular circuit.
2.This DMM accessory makes it possible to probe into the connector from behind without disconnecting
it.
Under what conditions should you check current flow in electrical/electronic circuits etc? - ANSWER:1.
Current flow tests are used when a circuit is suspected of having higher than normal current flow, such
as a dragging blower motor, or a circuit with a low-resistance short to ground.
In testing current flow with an ammeter or DMM, what is important to remember? - ANSWER:1. It is
important to remember that the test leads are connected in series with the circuit being tested, usually
at a point near the power source.
2.The circuit must be interrupted at some point to allow the connection of the test leads.
When do most DMMs have a 10-20 amp limit? - ANSWER:When measuring amperage directly through
the meter.
, -Any greater current flow will blow its fuse.
How should you test DMMS if you suspect that the circuit carries more than than a 10-20 amp limit? -
ANSWER:1. A safe way to test for current flow would be to use a current clamp.
2.This device simply clamps over the wire being tested and determines current flow by measuring the
strength of the magnetic field surrounding the wire.
3. While it is extremely handy to use, it is not as accurate as routing all the current through the DMM,
especially in circuits flowing less than 10 amps.
What is low current flow usually a result of? - ANSWER:Of excessive resistance in a circuit or low voltage.
2. Higher than normal current flow can generally be traced to excessive applied voltage or a shorted
component or wire.
How would you check continuity in an electrical circuit? - ANSWER:1. Auto-ranging DMMS do not have to
be adjusted to the range that is being measured.
3. While the purpose of this test is to make sure that a complete current path exists in the circuit being
tested, it is important to remember that it is not an accurate indication of circuit performance (e.g.,
excessive resistance).
4. A continuity test is most useful to quickly differentiate one circuit from another, such as trying to
locate a specific contact in a multiple pin connector.
What are the different ways continuity tests can be made? - ANSWER:1. If the circuit is energized, a
12/24 volt test light or voltmeter can be used to check for voltage at various test points.
2.Both tools accomplish this by energizing the circuit with low potential current to determine that the
circuit can be closed.
3. Many MMS have a separate feature on them that will allow continuity tests to be made simply by
listening for an audible beep.
4.This is handy because multiple tests can be made rather quickly, without having to look constantly at
the display for a resistance value.
What is essential when testing circuits that include electronic control modules (ECM)? - ANSWER:It is
essential to observe the original equipment manufacturer's (OEM's) diagnostic procedure to avoid
possible damage to the processor.
When are resistance checks typically made - ANSWER:When a circuit has unwanted voltage drops or low
current flow.
What is an ohmmeter? - ANSWER:1. A device that circulates a small current through a circuit when it is
not energized and then measures the voltage drop through it.
2. It displays the resistance (or restriction or resistance to current flow) in units know as Ohms.
What is the correlation between resistance value and electron flow? - ANSWER:The lower the resistance
value, the less restriction to electron flow there will be a circuit.
Answers
How are voltage tests measured? - ANSWER:Voltage tests are measured with the test leads of the DMM
in parallel to the component or circuit being tested.
How do you test applied voltage? - ANSWER:1. In testing applied voltage, the negative or black test lead
of the DMM is connected to a battery or chassis ground
2. The positive red lead is then probed near the power source (e.g. a switch or fuse) to determine if the
circuit is receiving the proper voltage.
What is a handy feature of a DMM? - ANSWER:Polarity is not important.
2. If the leads are reversed. the display will simply include a minus sign in front of the reading.
How are circuit voltages tested. - ANSWER:Take a positive test probe and go from one circuit's power
source to the next.
Generally, the applied voltages _______________. - ANSWER:Should be the same.
What is recommended when selecting a DMM to use for testing electronics circuits? - ANSWER:1. It is
recommended that it have a 10 megohm or higher impedance.
2.This is necessary to limit the effect the unit might have on accuracy when testing low current flow
circuits.
3.The lamp in the test light will draw too much current and this can damage the circuit integrity.
What should be done if it is necessary to test for voltage in an energized circuit - ANSWER:1. A
convenient way to do this is with a black-probe tool, also know as a "spoon," at various connectors in a
particular circuit.
2.This DMM accessory makes it possible to probe into the connector from behind without disconnecting
it.
Under what conditions should you check current flow in electrical/electronic circuits etc? - ANSWER:1.
Current flow tests are used when a circuit is suspected of having higher than normal current flow, such
as a dragging blower motor, or a circuit with a low-resistance short to ground.
In testing current flow with an ammeter or DMM, what is important to remember? - ANSWER:1. It is
important to remember that the test leads are connected in series with the circuit being tested, usually
at a point near the power source.
2.The circuit must be interrupted at some point to allow the connection of the test leads.
When do most DMMs have a 10-20 amp limit? - ANSWER:When measuring amperage directly through
the meter.
, -Any greater current flow will blow its fuse.
How should you test DMMS if you suspect that the circuit carries more than than a 10-20 amp limit? -
ANSWER:1. A safe way to test for current flow would be to use a current clamp.
2.This device simply clamps over the wire being tested and determines current flow by measuring the
strength of the magnetic field surrounding the wire.
3. While it is extremely handy to use, it is not as accurate as routing all the current through the DMM,
especially in circuits flowing less than 10 amps.
What is low current flow usually a result of? - ANSWER:Of excessive resistance in a circuit or low voltage.
2. Higher than normal current flow can generally be traced to excessive applied voltage or a shorted
component or wire.
How would you check continuity in an electrical circuit? - ANSWER:1. Auto-ranging DMMS do not have to
be adjusted to the range that is being measured.
3. While the purpose of this test is to make sure that a complete current path exists in the circuit being
tested, it is important to remember that it is not an accurate indication of circuit performance (e.g.,
excessive resistance).
4. A continuity test is most useful to quickly differentiate one circuit from another, such as trying to
locate a specific contact in a multiple pin connector.
What are the different ways continuity tests can be made? - ANSWER:1. If the circuit is energized, a
12/24 volt test light or voltmeter can be used to check for voltage at various test points.
2.Both tools accomplish this by energizing the circuit with low potential current to determine that the
circuit can be closed.
3. Many MMS have a separate feature on them that will allow continuity tests to be made simply by
listening for an audible beep.
4.This is handy because multiple tests can be made rather quickly, without having to look constantly at
the display for a resistance value.
What is essential when testing circuits that include electronic control modules (ECM)? - ANSWER:It is
essential to observe the original equipment manufacturer's (OEM's) diagnostic procedure to avoid
possible damage to the processor.
When are resistance checks typically made - ANSWER:When a circuit has unwanted voltage drops or low
current flow.
What is an ohmmeter? - ANSWER:1. A device that circulates a small current through a circuit when it is
not energized and then measures the voltage drop through it.
2. It displays the resistance (or restriction or resistance to current flow) in units know as Ohms.
What is the correlation between resistance value and electron flow? - ANSWER:The lower the resistance
value, the less restriction to electron flow there will be a circuit.
