1.
What materials make a good insulator?
Correct Answer
B. Ceramic and plastic
Explanation
Ceramics, plastics and rubbers are good insulators. They do not readily accept or give electrons.
2.
Tech A says AC stands for alternating voltage. Tech B says DC is used in electric motors on most hybrid vehicles. Who is correct?
Correct Answer
D. Neither Tech A nor B
Explanation
AC stands for alternating current. DC stands for direct current and is not used in hybrid vehicles to run electric motors.
3.
Tech A says high resistance causes an increase in current flow. Tech B says a voltage drop is another name for high resistance. Who is correct?
Correct Answer
B. Tech B
Explanation
High resistance does not increase current flow. Solve ohms law for constant voltage and infinite resistance. The drop of voltage in a circuit is a measurement of how much resistance there is in the part of the circuit being measured.
4.
Tech A says parallel circuits are like links in a chain. Tech B says total current in a parallel circuit equals the sum of the current flowing in each branch of the circuit. Who is correct?
Correct Answer
B. Tech B
Explanation
Parallel circuits are when the resistances are side by side, with individual power supplies and grounds. The sum of all of the current draws in a parallel circuit is the total current draw in the circuit.
5.
Tech A says relays are turned on and off by a small amount of current. Tech B says there are two types of relays: normally closed (NC) and normally open (NO) types. Who is correct?
Correct Answer
C. Both Techs A and B
Explanation
A small amount of current is used to energize the windings in a relay. They can either be normally open or closed.
6.
What does DVOM stand for?
Correct Answer
B. Digital volt-ohmmeter
Explanation
A DVOM is a digital volt-ohmmeter and is has that name because of what it tests and how it displays the measurement.
7.
When reading a digital volt-ohmmeter (DVOM), you have a reading of 2168 mV, which is the same as:
Correct Answer
D. Both A and B
Explanation
2168mV = 2.168 volts = 2168millivolts
8.
When probing wires, you should do all these EXCEPT:
Correct Answer
C. Reinsulate the hole with room temperature vulcanizing silicone.
Explanation
Never reseal a hole after probing with silicone.
9.
Tech A says you can measure up to 100 amps directly through the meter. Tech B says when checking high volts, you need to use a volt clamp so you don't damage the digital volt-ohmmeter (DVOM). Who is correct?
Correct Answer
D. Neither Tech A nor B
Explanation
Tech A claims that measuring up to 100 amps directly through a meter is possible, which is incorrect for standard DVOMs without a clamp adapter due to risk of damage. Tech B suggests using a "volt clamp" for high voltage measurements, a term misused, as voltage requires proper probes, not clamps. Both are incorrect.
10.
Tech A says most digital volt-ohmmeters (DVOMs) have both auto range and a manual range setting. Tech B says OL means overload and indicates the voltage being read is higher than the maximum. Who is correct?
Correct Answer
C. Both Techs A and B
Explanation
DVOMs have both a manual and auto setting. OL does mean you are measuring more than the maximum setting set on the meter.
11.
When doing a voltage drop test, the reading is 2.7 volts across the circuit. How many volts are going to the load?
Correct Answer
B. 9.3 volts
Explanation
The voltage drop test measures the difference in voltage across a circuit. In this case, the reading is 2.7 volts. Since the total voltage in the circuit is 12 volts, subtracting the voltage drop from the total voltage gives us the voltage going to the load. Therefore, the volts going to the load would be 12 volts - 2.7 volts = 9.3 volts.
12.
Tech A says testing across the battery will show you better voltage. Tech B says when checking across a switch, it has a 2-volt drop, which means only about 10 volts are going to the light. Who is correct?
Correct Answer
C. Both Techs A and B
Explanation
Testing from the battery directly will give you the best amount of voltage. The voltage drop is the difference of voltage in two different places in a circuit. What is left for the load is the drop amount, and its difference with battery voltage.
13.
Tech A says when doing a voltage drop test, the voltmeter needs to be set to ohm. Tech B says current has to be flowing to do a voltage drop test. Who is correct?
Correct Answer
B. Tech B
Explanation
DVOM needs to be set to test volts, and yes, you need a live circuit to test the voltage drop.
14.
Tech A says that in a relay, current is sent through a resistor and a magnetic field is produced. Tech B says to check the amps in a circuit, you need to connect the leads parallel to the circuit. Who is correct?
Correct Answer
A. Tech A
Explanation
A relay has two sides. The control side has a winding that gets charged and closes the switch on the other side of the relay. To read amperage in a circuit, you either need an amp clamp or to hook up the DVOM in series with the circuit.
15.
Tech A says when checking resistance in a circuit, you need to have power connected to the component. Tech B says ideally, you should have a component disconnected. Who is correct?
Correct Answer
B. Tech B
Explanation
A circuit does not need to be live to test for resistance. Having the component will keep from any feedback testing from happening.
16.
Tech A says Ohm's law will show how many amps are needed in a circuit with 110 ohm resistor and a 12-volt power supply. The amps needed are:
Correct Answer
C. 0.12 amps.
Explanation
Solve for ohms law. V=IR
17.
Tech A says there are three ways to check a circuit with Ohm's law. Tech B says if you know two of the measurements, Ohm's law will show you the third. Who is correct?
Correct Answer
C. Both Techs A and B
Explanation
You can check a circuit for resistance, voltage, and current. If you have two of the measurements, you will be solving for a single variable.
18.
When discussing a circuit, you know the voltage is 0.202 volts and the current draw is 0.00202 amp. What is the resistance in the circuit?
Correct Answer
C. 100
Explanation
Solve for ohms law. V=IR
19.
When doing a voltage drop test, you should do all these EXCEPT:
Correct Answer
C. Remove the positive battery cable.
Explanation
If you're doing a voltage drop, you need the circuit to be live. Disconnecting the battery cable will open the circuit.
20.
Tech A says you can calculate total circuit current with this formula I = V ÷ R. Tech B says you can determine the total voltage drop using Ohm's law. Who is correct?
Correct Answer
C. Both Techs A and B
Explanation
Ohm's law is V=IR, no matter how you arrange it. You can use Ohm's law to determine the total drop of voltage.
21.
Tech A says voltage drops can be measured as long as current is flowing. Tech B says voltage drops can be measured across components, connectors, or cables. Who is correct?
Correct Answer
C. Both Techs A and B
Explanation
You need current flow to measure a drop in voltage, and can be done across any kind of circuit or load.
22.
When calculating current flow in a parallel circuit that has 4 resistors, you would:
Correct Answer
C. Add the current flow for each resistor together.
Explanation
The sum of the resistances in a parallel circuit equals the total current flow in the circuit.
23.
A variable resistor:
Correct Answer
C. Has a movable arm that swipes across a coil that has less resistance at one end and more at the other.
Explanation
Think of a fuel level sensor, also known as a sending unit.
24.
Tech A says checking a variable resistor is almost the same as a regular resistor. Tech B says you have to have a different type of digital volt-ohmmeter (DVOM) to read a variable resistor. Who is correct?
Correct Answer
A. Tech A
Explanation
A resistor is a resistor. There are only small differences between them. There is only one kind of DVOM.
25.
Tech A says an oscilloscope is commonly referred to as a lab scope or just scope. Tech B says lab scopes are not very important test instruments in a modern automobile. Who is correct?
Correct Answer
A. Tech A
Explanation
Yes, the scope is commonly referred to as either of the three listed, and are very important instruments in testing and inspecting faults with modern automobiles.