Chapter 63

Printed circuit boards often have two layers and as many as ___ layers to accommodate the complex circuitry.

16

The range of human hearing is approximately _______ cycles per second to _______ cycles per second.

20; 20,000

A small current in the transistor base allows ____________ through the emitter-collector junction.

A larger current to flow

_______ signals are continuously variable, typically changing in strength and time.

Analog

Control modules are being discussed. Technician A says that there may be more than 115 ECUs installed on a vehicle. Technician B says that the ECUs all communicate with one another via the vehicles network. Who is correct?

Both Technician A and Technician B

Switches are being discussed. Technician A says that non-ECU switches directly control a circuit's operation. Technician B says that ECU-controlled switches are used as inputs to a control unit which then controls a circuit. Who is correct?

Both Technician A and Technician B

Technician A says that a CTS and IAT sensor are examples of thermistors. Technician B says that there are two common types of thermistors: an NTC and a PTC. Who is correct?

Both Technician A and Technician B

Technician A says that a component that requires full voltage but can be controlled by varying the time is typically pulse-width-modulated. Technician B says that a component that can operate with lower than full voltage can be controlled by changing the duty-cycle. Who is correct?

Both Technician A and Technician B

Technician A says that a fuel injector is a component that requires precise control, using pulse-width-modulation. Technician B says that a radiator fan is an example of a component that can be controlled by controlling duty cycle. Who is correct?

Both Technician A and Technician B

Technician A says that a potentiometer can be tested for larger faults with a DMM. Technician B says that a potentiometer may need to be tested with an oscilloscope to find smaller faults. Who is correct?

Both Technician A and Technician B

Technician A says that a scan tool can activate some circuits, eliminating the need for a switch, which can be helpful in the diagnosis. Technician B says that the data list can show circuit input values and help in the diagnosis. Who is correct?

Both Technician A and Technician B

Technician A says that analog signals are continuously variable signals. Technician B says that digital signals are direct on/off signals with no in-between transition. Who is correct?

Both Technician A and Technician B

Technician A says that diagnosing computer controlled circuits is the same as any other electrical circuit. Technician B says that most computer controlled circuits can also be diagnosed with a scan tool. Who is correct?

Both Technician A and Technician B

Two technicians are discussing transistors. Technician A states that transistors are used as a switch or an amplifier. Technician B states that transistors use a very small current in the base to control a much larger current. Who is correct?

Both Technician A and Technician B

Which of the following is the best tool to measure the voltage output from a throttle position sensor?

DSO

In a switch input circuit, the load in the circuit is referred to as a(n) __________.

Dropping resistor

Which type of sensor is typically used as a crankshaft or camshaft position sensor?

Hall effect

Which of the following is NOT a type of digital speed sensor?

Inductive

A Zener diode has special characteristics. What are those?

It blocks current flow until the voltage is large enough to force current through it.

Technician A says that a pressure switch sends a varying electrical signal, based on pressure, to an ECU. Technician B says that pressure sensors send an electrical signal that is an on/off signal.

Neither Technician A nor Technician B

Technician A says that a pulse-width-modulated signal can only be measured with a DMM. Technician B says a duty cycle can only be measured with a DSO with a special testing adapter. Who is correct?

Neither Technician A nor Technician B

Technician A states that digital signals are continuously variable, typically changing in strength and time. Technician B states that an analog signal is a direct on/off with no in-between transition. Who is correct?

Neither Technician A nor Technician B

What type of position sensor uses an LED and photo diodes separated by a shutter wheel?

Optical sensor

The junction of a diode is called a:

PN junction.

The on and off time of a stepper motor relates to it's duty cycle, which is generally expressed as a:

Percentage.

A(n) __________ is a resistor with a mechanically variable wiper that can change a voltage as it moves.

Potentiometer

What do some sensors use to create a variable voltage signal that corresponds to a specific condition?

Potentiometer

Which of the following position sensors is NOT used for rotating components such as a crankshaft or wheel?

Potentiometer-type sensor

A variation in pulse width at a fixed frequency is called:

Pulse-width modulation.

Technician A says that most Hall effect sensors can be completely tested with an oscilloscope. Technician B says that a DMM set to measure AC voltage can be used to test a Hall effect sensor. Who is correct?

Technician A

Technician A says that vehicle network speed where different ECUs communicate with one another is referred to as a baud rate. Technician B says that the baud rate for all of the ECUs is the same, regardless of the ECUs function. Who is correct?

Technician A

Technician A says that when an engine with an NTC coolant temperature sensor increases in temperature, the internal resistance decreases. Technician B says that when an engine with an NTC coolant temperature sensor increases in temperature, the internal resistance increases. Who is correct?

Technician A

Technician A says that all ECU controlled circuits operate by controlling the 12-volt, positive side of the circuit. Technician B says that ECU input and output circuits may not operate at source or ground voltage. Who is correct?

Technician B

In a vehicle, thermistors are used in various sensors related to:

Temperature.

A __________ can assist a technician by verifying measured voltages as being correct.

Terminal pin check chart

A resistor that changes it's resistance with changes of temperature is called a:

Thermistor.

Pressure sensors are typically __________- wired sensors.

Three

The potentiometer can be linear or circular in construction and has _______ electrical connecting points.

Three

Which of the following is NOT an example of an electronic control unit?

Throttle Position Sensor (TPS)

Which of the following is NOT an example of a thermistor?

Throttle position sensor

Which of the following is NOT an example of a pressure sensor?

Variable resistor

When cycled very quickly, digital signals can be used to create a(n) _______, similar to the variable control provided by an analog signal.

Varying output control signal

An application of zener diodes in vehicles is the:

Voltage regulator.

A __________ can help a technician trace current paths and identify inputs and outputs.

Wiring diagram

Which of the following is NOT a part of a computer-controlled system?

react