Unit 1a

Which transformer is used in audio frequency range from 15 Hz to 20 kHz?

*Audio Frequency Transformers

What is the insulator material separate 2 plates in capacitor called? What's the purpose of it?

*dielectric, to keep charged particles apart

What is operation of emitter-based junction?

- Forward Biased - Reduces size of the EB junction barrier - Lowers EB junction resistance

What is operation of Collector-Base junction?

-Reverse Biased -Increases size of the CB junction barrier -Raises CB junction resistance

How many diodes does a half-wave rectifier have?

1

What are three conditions necessary for induction?

1. Conductor (coil) 2. Magnetic field 3. Relative motion

What are the two bias of a PN Junction diode, and how do they connect to the battery?

1. Forward bias - positive battery terminal connects to P-type material, vice versa for negative 2. Reverse Bias - positive battery terminal connects to N-type material, vice versa for Negative

What are the three classes of Integrated Circuit (IC):

1. Linear (Analog) - RF, video, servo, operational amplifiers, & voltage regulators 2. Digital - electronic circuits that use voltage/current levels. Computers, Switching gates, flip-flops, counters, comparators, adders, & memories 3. Mixed - Mixed-signal circuits refers to integrated circuits (ICs) which have both analog circuits & digital circuits combined on a single semiconductor.

What are the four factors that affect how a resistor resists or opposes movement of electricity?

1. Material (p) 2. Length (l) 3. Cross sectional area (A) 4. Temperature

Limitations of integrated circuits are:

1. Power and voltage - Small sized & closely packed components 2. 2. 2. Component - Cannot put inductors, transformers, large capacitors on chip

What are the five Scales of Integration for integrated circuits?

1. SSI (small-scale integration): Up to 100 components per chip 2. MSI (medium-scale integration): From 100 to 3,000 components per chip 3. LSI (large-scale integration): From 3,000 to 100,000 components per chip 4. VLSI (very large-scale integration): From 100,000 to 1,000,000 components per chip 5. ULSI (ultra large-scale integration): More than 1 million components per chip

What are the five mechanical parts that make up a relay?

1. Stationary coil 2. core 3. Contacts mounted on a frame 4. A movable armeture (pole) 5. Spring

What are advantages for the small size of Integrated circuits?

1. This saves money on floor space, cabinets, wire, and hardware. 2. Small circuits consume less power thus requiring less air-conditioning equipment. 3. The small size will increase the operating speed of a system because the travel time for information between parts of the system is shorter

What are the three purposes of a transistor?

1. To function as an electronically controlled variable resistance; 2. to act like an electronically controlled switch; 3. as an amplifier.

What are the two PN junctions in each transistor?

1. between the emitter and the base. This is called the Emitter-Base or the EB junction. 2. between the collector and the base. This is called the Collector-Base or the CB junction

Current in the armature changes direction every ___ degrees of rotation.

180

If a schematic has no phase dots on the transformer, what phase shift is assumed?

180 degrees

What are 5 mains parts of relay?

A core, coil, armature and contact spring

What Provides electrical power in motor vehicles, in various military and industrial applications, including the generation of commercial power.

AC generators (alternators)

what type of generator is generally capable of producing a pure sine wave output voltage of constant frequency?

AC generators, more commonly known as alternators,

_________ current periodically changes direction as the voltage changes _______.

AC, polarity

Electron will always flow _______.

Against the arrow. The PNP transistor current flow will enter into the collector and into the base and out of the emitter. The NPN transistor current flow will enter into the emitter and out of both the collector and base

What type of inductor has an insulated core?

Air core

What are the two types of inductors and what it's used for?

Air-core inductor: often used in radio frequency circuits Iron core inductor: often used in audio frequency and power circuit

The two elements of the diode?

Anode (arrowhead) (P-type material) and Cathode (bar)(N-type material)

In AC operation the capacitor charges and discharges at the same frequency of the

Applied voltage

What carries a relay's movable contact?

Armature

Which relay component carries the movable contacts?

Armature

Normal current flow through a Zener diode is with the ____

Arrow

Which transformer is the only one that will pass direct current?

Autotransformers

Which transformer type uses one winding for both the primary and secondary circuits?

Autotransformers

Battery life is dependent upon

Battery age Temperature Charge times Amount of use

How does capacitor opposes changes in voltage?

Block DC, passes AC

________ are small blocks of carbon-graphite, which provide a current path to the rotating slip-ring.

Brushes

What is the formula for capacitor and what each letter means?

C=KA/d C= capacitance K = material in between A = how big plates are D = how far apart plates are

The ability of a capacitor to temporarily store electrical energy in the

Capacitance

What is the ability to store an electrical charge, measured as the difference of potential between the two plate areas across an insulator (dielectric)?

Capacitance

What is a component that stores energy in an electrostatic field and opposes changes in voltage?

Capacitor

Most filter circuits use single ____ or pair of _____ coupled with a _______.

Capacitor; Resistor

What does an armature do in a relay?

Carries the relay's moveable contacts. When the relay is energized, the armature moves from its normal position to its energized position in response to the magnetic field created around the coil/core.

What component item is made of several turns of insulated wire wrapped around each of the pole pieces which forms the rotor

Coil

1.What is the purpose of Diodes?

Conduct current freely in one direction and oppose current flow in the opposite direction

Inductors are constructed by winding a ________ around a core. The wire is very close, therefore, ________ is required

Conductor, insulator

In an AC circuit, a capacitor will discharge:

Constantly

Diodes utilize this type of semiconductive material to create the PN Junction.

Crystals

How does current flow in a diode?

Current always flows from negative to positive in circuit (forward bias)

What happens when power is applied to the primary circuit inside of a relay?

Current flows creating a strong magnetic field around the coil

What happens when power is applied to the primary circuit?

Current flows creating a strong magnetic field around the coil

What is the point at which a further decrease in forward bias does not results in a decrease in collector current; transistor acts like an

Cutoff; transistor acts like an OPEN or OPEN SWITCH

What is the material between the plates of a capacitor called?

Dielectric

In a capacitor, what is the non-conductive region that separates two conductive surfaces called plates?

Dielectric (insulator)

The main disadvantage of the rotating armature design is what?

Disadvantage is that heavy load current flows from the slip rings to the brushes, which are then subject to arcing.

An inductor stores energy in what field?

Electro-magnetic field

Relays/solenoids are _____ devices

Electromagnetic

What type of field does a inductor store energy in?

Electromagnetic

What is the creation of voltage and current within a conductor by varying the magnetic field affecting that conductor called?

Electromagnetic Induction

How do transformers transfer electrical power between circuits?

Electromagnetically

When a bar magnet suspended in the air and free to move will be attracted or repelled by another magnet brought close to it is considered to be

Electromagnetism

How does a capacitor store energy?

Electrostatically

The transistor is constructed in three layers

Emitter - medium size, gives off or "emits" current carriers (either electrons or holes). Base - very small, controls the flow of the current carriers. Collector - large, collects the current carriers.

PN Junctions diodes use bias, for Forward Bias and Reverse Bias the diodes act like which kind of switch?

FB diode= closed switch (Positive side of power to P-type material (Negative to N-type) RB diode= open switch (Negative side of power to P-type material) (Positive to N-type)

Inductors oppose DC continuously.

False

T/F Brightness of an LED depends on the diode material.

False brightness of an LED is directly dependent on how much current it draws

T/F Reverse bias is current flowing from negative to positive, cathode to anode.

False forward biasing occurs when the voltage across a diode permits the natural flow of current, whereas reverse biasing denotes a voltage across the diode in the opposite direction.

T/F A step-up transrormer increases current

False. Explain: A step up transformer works simply by having more turns of wire on the secondary side. This increases the voltage but it decreases the current. A step down transformer works by having less turns of wire on the secondary side. This reduces the voltage but increases the current.

What type of capacitor is used in circuits that require stable capacitance and very temperature-stable?

Film

Which type of resistor provides a constant unchangeable amount of resistance?

Fixed resistor

Name the three basic types of resistors.

Fixed, tapped, and variable

How many diodes does a full-wave rectifier have? How many output pulses?

Four diodes; two output pulses

What component item of stator supports the pole pieces and coils?

Frame

Which rectifier is the easiest to filter?

Full-wave rectifier

What converts mechanical energy into electrical energy.

Generators

What is the unit of measurement and symbol for inductor?

Henry and symbol is H

______ support brushes and springs, and align them with the slip-rings.

Holders

What are two basic types of relays that are used in many different applications?

Holding relay + overload relay

How does inductors operation differs in AC/DC Operation?

In DC Operation it only opposes the change in currency when the circuit is turned on or off, in AC operation the opposition to change occurs constantly because of the nature of AC changing directions

What is a component that stores energy in an electromagnetic field and opposes a change in current?

Inductor

In addition to its normal DC resistance, an ______ offers an _______ to a change in current flow.

Inductor, opposition

Describe the process of how an inductor is constructed =

Inductors are constructed by winding a conductor (solid copper wire coated with enamlel insulation) around a core.

What is a circuit designed to serve a portion or all of an electronic function and consists of transistors, diodes, resistors, and some small capacitors? Also made its way into virtually all-electronic equipment manufactured today.

Integrated circuit

What kind of relationship does forward bias and junction barrier resistance have?

Inversely proportional

What does changing the amount of bias do to transistor?

It's resistance changes and therefore will allow more or less current to flow through it.

What is the schematic symbol for a relay?

K

The schematic symbol for a relay is _______ and the relays are always shown in the _________ condition unless otherwise indicated

K; de-energized

most radio systems use what type of battery? And why?

Lithium-ion battery packs due to lithium batteries being lightweight, having high power capacity, no memory effects, and a longer shelf-life.

Electrical current through a wire generate a ________

Magnetic field

How do electromechanical relays actuate?

Magnetically

What are some non-conductive materials that is best used in a capacitor's dielectric?

Mica, ceramic, cellulose, porcelain, Mylar, teflon, and even air

What is a pole?

Movable contact of relay

What process does electrons go through during junction recombination?

N- and P-type materials are joined, and the free electrons of the N material begin to spread out across the junction into the P material and the free electrons of the N material see the holes of the P material as vacancies and fills them.

The cathode is __-type, so the pulses are ____

N-type; negative

Transistors are classified as __________ or _________ according to the arrangement of the N and P type materials.

NPN (Negative-Positive-Negative); PNP (Positive-Negative-Positive)

PN Junction Diode has what kind of temperature coefficient? Explain?

Negative temperature coefficient, the lower the temperature the more resistance.

What is a Throw?

Number of switch options

What is resistance measured in?

Ohms

Diodes are used to conduct current in _____ direction. And opposed current in the _____ direction.

One; oppose

The three mains types of Diodes covered in this section are _____, _____, _____.

PN Junction, Zener, LED

What aspect of a diode determines its resistance?

PN junction width

Many RF career field radio systems, such as the ______, utilize multi-cell configurations. Also utilizes rechargeable lithium batteries.

PRC-160

What uses waxed paper for the dielectric with flat strips of tin foil for the plates. Also known as the most common, and most inexpensive type of Capacitor

Paper capacitor

What component item are made of laminated, soft steel segments around which the coils are wound?

Pole pieces

In a zener diode current flows from _____ to ______ in the direction the arrow is pointing.

Positive (anode) to negative (cathode)

Which type of variable resistor controls voltage?

Potentiometer

Which type of variable resistor is used to control or vary the amount of voltage used in circuits?

Potentiometer

Which transformer is mainly used in power distribution circuits?

Power transformers

What are the types of transformers?

Power transformers, audio frequency transformers, radio frequency transformers and autotransformers

Current applied to which circuit in a relay actuates the switch?

Primary

Which resistor is integrated into a cirbuit board?

Printed carbon

What is a spring used for in a relay?

Provides the constant restraining force that keeps the armature in the normal or de-energized position.

The schematic symbol for a transistor is labeled with a ____; emitter is labeled with an _____; The base is represented by a ____. The collector is the ____ lead,

Q; arrow; bar; third

What is the symbol for resistance?

R

What is the formula for resistance?

R = p * L / A , where p is resistivity, L is length, and A is area

Which transformer is used for frequencies just above the audio range?

Radio Frequency Transformers

Determines the polarity of the output DC voltage

Rectifier

What is specifically designed to oppose current flow in electrical circuits?

Resistors

When the relay becomes de-energized, what does the spring do?

Return the armature back to normal, de-energized position

Which type of resistor can change its resistance while the equipment is in operation?

Rheostat

Which type of variable resistor I used to control or vary the amount of current used by a component or circuit?

Rheostat

Which side of the transformer symbol is the load usually showed on?

Right

What is the difference between the minimum DC voltage and the maximum DC voltage in the filtering stage?

Ripple voltage, or just ripple

This design induces voltage into the rotor coils by rotating them inside the field (stator coils.) This makes the rotor the armature. (Output taken from the rotor)

Rotating armature design

What design has the output taken from the stator? (the stator coils become the output coils making the stator the armature)

Rotating field alternator

The pulsating DC has current increasing or decreasing but always in the ________ direction.

Same

What is the point at which a further increase in forward bias does not results in an increase in collector current? How does transistor act?

Saturation; acts like a SHORT or CLOSED SWITCH

Rotor consist of four component items:

Shaft, core, coil, and slip rings

In DC operation when Ic current is maximum and c voltage capacitor is acting like a _____. And vice versa??

Short Open

In a single cell battery figure, what does shorter line and longer line in middle of both symbols represent?

Shorter line: negative terminal Longer line: positive terminal

The ______ regulator will also correct for voltage changes that may occur due to changes in the resistance of the load device.

Shunt

______ regulator has limitations to its output voltage regulation

Shunt

______ push the brushes firmly against the slip-rings to maintain good electrical contact

Springs

Define the terms "step up/step down"

Step up: means that voltage or current is being increased in value from the primary to the secondary Step down: means that the voltage or current is being reduced from primary to secondary

Which resistor type has no leads?

Surface mount

Which type of resistor has the ability to change the amount of resistance?

Tapped resistor

Which condition is not necessary for induction?

Temp

How can transistor act as an amplifier?

The bias of the transistor will control the circuit current which will control the voltage drops across the circuit components. By varying the bias, the transistor can take small changes in amplitude and create large changes in amplitude, amplification.

What does it mean that a PN Junction Diode is a non-linear device?

The circuit's voltage and current does not have to change at the same rate!

What two components works as an inductor to move the armature?

The core and coil

If the temperature of a PN junction diode increases, more current flow because _____.

The resistance of the semiconductive material has decreased

What is a rheostat used for in the circuit?

The rheostat is used to control or vary the amount of current used by a component or circuit. Used in applications that require the adjustment of current or the varying of resistance in an electric circuit.

What alternator is widely used because of its greater efficiency; it can develop more useable power for a given physical size. It has three single-phase windings spaced so that the voltage induced in each armature winding is 120° out of phase with the voltages in the other two armature windings.

The three phase alternator

Which alternator produces most commercial power?

Three-phase alternators

In the PNP, the arrow will point ______.

To the base (pointing in pointer)

What is a alternating current (ac) device that is used to transfer electrical power from one circuit to another by means of electromagnetic field?

Transformer

What is an alternating current (AC) device that is used to transfer electrical power from one circuit to another by means of an electromagnetic field?

Transformer

What is a semiconductor device that have three or more electrodes?

Transistors

Autotransformers are the only transformer that will pass direct current (T/F)

True

Current passes through the coil of an inductor.

True

In a dc circuit, opposition to a change occurs only when the circuit turned on or off.

True

T/F Batteries provide Direct Current (DC) power, therefore they are considered a DC power source.

True

T/F Capacitors allow AC current to pass but block DC current.

True

T/F Diodes have a non-linear resistance.

True

T/F Distance between the plates inversely affects capacitance.

True

T/F In all motors, and DC generators, the terms "rotor" and "armature" are synonymous.

True

T/F The cathode of a diode is negative.

True

What is a potentiometer used for in the circuit?

Used to control or vary the amount of voltage used in circuits.

Which type of resistor is able to be changed during operation?

Variable resistors

________ are necessary to maintain a constant output voltage level.

Voltage regulators

How does Mutual induction work?

When AC voltage is applied to the primary of the transformer, The current flows which results in the expanding and collapsing of magnets generating a magnetic field. Through the magnetic flux lines forcing expansion and collapsion of the secondary winding, it induces an AC voltage in the secondary. Creating current in the secondary creating an additional magnetic field within. The secondary magnetic field then interacts with the primary magnetic field reducing the primary CEMF and increasing the overall primary current.

When is a voltage divider considered unloaded?

When no external load device is connected

What can transformers be classified by?

Winding style, frequency range, and/or power application

_______ diode is in parallel or "shunt" to the load device.

Zener

What kind of bias does a PN Junction and Zener Diode use?

Zener Diode uses a reverse bias and PN Junction uses a forward bias.

Basic alternator theory consists of three main factors which are all required to mechanically generate electricity:

a conductor, magnetic field and relative motion.

Generator output is regulated to ensure what?

a stable voltage and current under varying load conditions.

What is NPN transistor is constructed of?

a very thin and lightly doped base region of P-type material separating two heavily doped regions (emitter and collector) of N-type material

In order for a transistor to function normally, the following rules apply:

a. The Emitter-Base (EB) junction must be forward biased. b. The Collector-Base (CB) junction must be reverse biased.

How can a transistor act like an electronically controlled switch?

accomplished by applying too much or too little bias forcing the transistor to "act" open or closed.

The NPN transistor can be compared to two diodes, connected _______.

anode-to-anode

In the NPN, the arrow will point _______.

away from the base (not pointing in)

Brush Consists of a ______, _____, and ____ for each slip-ring.

brush, spring, holder

The different types of batteries include:

carbon zinc, alkaline, sealed lead acid, and lithium

The PNP transistor can be compared to two diodes, connected ________.

cathode-to-cathode

Changes in transistor current can cause what?

changes in the bias voltages, possibly forcing a transistor to go into saturation or cutoff.

Many DC circuit load devices require _____ voltage in order to operate.

constant steady

What is the purpose of a power supply?

convert AC voltage to DC voltage for use in circuits where AC voltage is not acceptable.

The ____ is made of stacks of laminated, curved, soft iron plates

core

The _____ of the diode determines the polarity of the output pulses

direction

Batteries convert chemical energy into_________

electrical energy.

What are some example of solenoid relays?

electrical switching (car starter circuit), mechanical motion (electrical door lock)

Generators operate on the principle of ___________ induction.

electromagnetic

What are types of capacitor?

fixed, electrolytic, and variable

There are three distinct types of rectifier circuits:

half-wave, full-wave, and and full-wave bridge

How does a center tapped transformer work?

indicates a center tap that will divide the signal applied from the primary winding into two signals. These Signals are equal in aptitude and are positioned 180 out of phase from each other.

Unlike resistor-capacitor filters, ________ filters do not significantly reduce DC output voltage.

inductor-capacitor

Temperature and resistance are ________ proportional

inversely When the temperature of a transistor increases, its resistance decreases, and the current flow through it increases. The reverse is also true. If the temperature of a transistor decreases, its resistance increases, and the current flow through it decreases.

The voltage regulator's purpose is to

keep the output voltage constant (steady) under changing input voltage or load resistance condition.

Integrated circuits are made from what?

made from a silicon wafer using a complex photographic process in which layers and layers of doping are added until the circuit is formed. Because this is a photographic process, the size of the components can be reduced microscopically.

Transistors have a _____ temperature coefficient of resistance

negative

What is the turn ratio formula for voltage?

np/ns=Ep/Es

The anode is __-type, so pulses are _____.

p-type; positive

The output frequency is measured in

pulses per second (pps)

The task of converting AC into DC is called

rectification

the _____ is a diode (or collection of diodes) that convert AC voltage into pulsating DC voltage

rectifier

What are the two types of alternators:

rotating armature and rotating field

What alternator is the most efficient way to produce alternating current?

rotating field alternator

The _____ is a rotating axle holding the core and coils

shaft

The _______, which are copper rings insulated from each other. One slip-ring is connected to each end of the rotor

slip-rings

The three advantages of integrated circuits (IC) over discrete circuits are:

small size low cost high reliability. Easy to troubleshoot

The pulsating DC is applied to the filter section and is converted into ______ DC.

smoother DC

With alternators "Armature," always refers to

the coils supplying the output voltage.

What are the three component items for stator:

the frame, pole pieces, and coils.

The output frequency of a half-wave rectifier is _________ the frequency of the input AC

the same as

Alternators have three major assemblies:

the stator, rotor, and brush.

The input voltage from the AC source is applied to the _____, which is capable of stepping up or stepping down the voltage

transformer

T/f Always read and follow any and all WARNINGS, CAUTIONS, and NOTES concerning batteries.

true

The output frequency of a full-wave rectifier is ________ the frequency of the input AC

twice

In DC operation, when will current and voltage are zero?

when capacitor is fully discharged

How does Capacitor resists changes in voltage?

▪Builds up charge across plates when input voltage increases. ▪Voltage across plates decreases more slowly than input voltage, leveling out ripple voltage.