Ch.3

What are the steps for connecting an LED?

1. choose the correct resistor. 2. determine polarity for forward bias 3. anode to positive circuit 4. cathode to negative circuit 5. current flows, light emits

Technician A says that applying voltage to the base of an NPN transistor will allow current to flow from the collector to the emitter. Technician B says that applying voltage to the collector of an NPN transistor will allow current to flow from the base to the emitter. Which technician is correct?

A

Technician A says that if you remove the power from the gate on an SCR, all current flow will stop through the SCR. Technician B says that SCRs are used in a high-mounted stop light to keep the third brake light from blinking when the turn signals are used. Which technician is correct?

B

MOSFET transistors are constructed the same as a JFET. T/F?

F

MOSFET transistors control the emitter voltage changes the base voltage. T/F?

F

MOSFET transistors have an aluminum dioxide insulator between the gate and the semiconductor material. T/F?

F

emits a light when forward voltage is applied

LED

switches or amplifies electronic signals

MOFSET

MOSFET transistors are commonly found in car stereo amplifiers. T/F?

T

MOSFET transistors control the gate voltage changes the current passing from the source and drain. T/F?

T

positioned backwards in the circuit

Zener

Technician A says a junction diode can be thought of as a one-way check valve for electron flow. Technician B says that a photodiode will produce light when it is forward-biased. Which technician is correct?

a

(In regards to what type of sensor this refers to ) generate their own signal and do not require a reference voltage to function

active sensors

(considering diodes) attached to the positive side of the circuit

anode

Technician A says that diodes allow current flow in two directions. Technician B says that because a semiconductor has no moving parts and rarely wears out or needs adjusting, it functions as a good switch. Which technician is correct?

b

Technician A says that a Zener Diode functions like a regular diode until a breakdown voltage is reached. Technician B says that once the breakdown voltage level of the diode is reached, current is allowed to flow in the opposite direction. Which technician is correct?

both

(considering diodes) attached to the ground side of the circuit

cathode

current flows through the diodes (considering diodes)

completed circuit

(In regards to what type of sensor this refers to ) output an on/off or binary signal

digital sensor

low resistance to current in one direction and high resistance to current in the other

diode

uses less current and mostly relies on a low-voltage signal to control an electrostatic field

field-effect

(considering diodes) electrons and holes meet

forward-biased junction

(In regards to what type of sensor this refers to). rely on a reference voltage supplied by the control module

passive sensors

has a window built into the housing that responds to different wavelengths of light

photodiode

MOSFET transistors can control a higher current than a JFET. T/F?

t

(In regards to what type of sensor this refers to ) are typically passive type

three-wire sensors

three-terminal device that switches, amplifies, or oscillates electrical signals

transistor

(In regards to what type of sensor this refers to ) can be either passive or active

two-wire sensors