17. Electronics Information

Question 1

What is electricity?

Answer 1

Electricity is a general term for the variety of phenomena resulting from the presence and flow of electric current.

Question 2

Electricity is measured in three ways, what are those? synthesize.

Answer 2

1. Volts: Volts measure the difference of potential between two points.
2. Amperes (amps): Amps measure the number of electrons that move past a specific point in 1 second.
3. Ohms: Ohms measure resistance, including anything that could limit the flow of electrons.

Question 3

Synthesize the following terms: Current, Watt, Watt-hour, Kilowatt and kilowatt-hours, Megawatt, and Megawatt.

Answer 3

• Current: Electricity is like water — it flows. Electrical current occurs when electrons move from one place to another. The use of conductors, such as copper and water, allows the electrons to move freely. Insulators, such as rubber and wood, discourage the electric current.
• Watt: A watt measures power, the rate at which electrical energy is consumed or transformed into another type of energy, such as light or heat.
• Watt-hour: A watt-hour is the amount of energy used in 1 hour at a rate of 1 watt. Most electricity is measured in kilowatt-hours, which is how much energy you’d use if you ran a 1,000-watt (1-kilowatt) device for an hour. For example, 10 kilowatt-hours is enough energy to run a 10,000-watt speaker system for an hour-long outdoor concert, or it could run a 5,000-watt air conditioner for 2 hours or a 1,000-watt waffle iron for 10 hours. You find watt-hours by multiplying wattage by time (expressed in hours).
• Kilowatt and kilowatt-hours: One kilowatt (kW) equals 1,000 watts, and one kilowatt-hour (kWh) is one hour using electricity at a rate of 1,000 watts. Kilowatt-hours are what you see on your electricity bill; they’re useful for measuring large amounts of electricity.
• Megawatt: Megawatts (MW) are tremendous. One megawatt is equal to 1,000 kilowatts (and 1,000,000 watts). This unit measures things like power plants or how much electricity an entire city uses.
• Gigawatt: Gigawatts (GW) measure the capacity of large power plants (or multiple smaller power plants). One gigawatt is equal to 1,000 megawatts and 1 billion watts. (Rumor has it that 1.21 gigawatts can power a time machine).

Question 4

What is the valence shell?

Answer 4

Valence shell is the number of electrons in the outer shell of an atom, and it determines whether an element is a conductor, semiconductor, or insulator.

Question 5

What is the difference between conductors, semiconductors, and insulators?

Answer 5

1. Conductors allows electrons to flow freely between different atoms. these valence shells have more empty spots than they have electrons.
2. Semiconductors have half-full valence shells (or half-empty, depending on your attitude) and are neither good conductors nor good insulators.
3. Insulators have pretty full valence shells (at least more than half), so electrons can’t move much (or at all) between atoms. They’re very poor conductors.

Question 6

What is an electrical current?

Answer 6

Electric current is the flow — or, more precisely, the rate of flow — of electrons in a conductor. Electrons carry an electrical charge that is expressed in coulombs (C).

If 1 Coulomb flows past a specified point in 1 second, that’s a flow rate of 1 ampere.

Question 7

What is an ampere?

Answer 7

An ampere represents the movement (flow) of electrons, so electrical currents are measured in amps. Typically, current is tiny, so small that it’s measured in milliamperes; 1 milliampere is one-thousandth of an ampere. Current meters, called ammeters, measure the flow of current through a circuit. You can compare the flow of electrons to water coming from a garden hose; amps are equivalent to gallons-per-minute if you are washing your car in the driveway.

Question 8

What is a circuit breaker?

Answer 8

Sometimes a circuit must be opened in order to add or remove resistance. In other words, the flow of the electricity must be interrupted in order to physically change the resistance. Using a circuit breaker, which is a device that automatically interrupts the electrical current, is an example of opening a circuit control the current. When the circuit breaker trips, the electrical device can no longer operate.

Question 9

What is a rheostat?

Answer 9

Some devices use a rheostat, which can vary the resistance without opening the circuit — the device can continue to work even as the resistance is altered. If an application doesn’t use all the electricity, the rheostat absorbs it. A dimmer switch on a light is an example of a rheostat. You increase the amount of resistance to dim the light and decrease the resistance to brighten the light.

Question 10

If you have a current flowing through a wire, three influences are present, what are those?

Answer 10

1. The amount of voltage, measured in volts (V) or electromotive force (EMF).
2. The resistance to the current, measured in ohms (Ω).
3. The amount of current, measured in amperes and expressed as I or i

Question 11

What is the definition of the word Ohms? & What is Ohms law?

Answer 11

The amount of resistance that interferes with the flow is measured in ohms (pronounced just like those yoga chants).

Ohm’s law, which was first stated by Georg Simon Ohm, reads, “The current in a circuit is directly proportional to the applied voltage and inversely proportional to the circuit resistance,” but it’s actually easier to understand in mathematical terms. When stating the relationship mathematically, abbreviations are used, where I is current, V is voltage, and R is resistance:

Current (amperes) = Voltage (volts)/Resistance (ohms), or I=V/R

Question 12

What is voltage?

Answer 12

Voltage is the difference of the pressure between two points in a circuit. It’s sometimes called the voltage drop or difference of potential.

Question 13

In electronics, what is the term ground?

Answer 13

Ground is any part of a circuit (or other object that has electricity running through it) that measures 0 volts, such as the case of your radio, the base of a lamp, or the chassis of your car. The negative terminal of 9-volt battery is at ground potential, so the voltage from the negative terminal of the matter measures 9 volts.

Question 14

How can you measure the voltage in a circuit?

Answer 14

You might need to use a voltmeter or a multimeter, which has several meters in one instrument. A voltmeter has two leads. To measure voltage, you place one lead somewhere in the circuit and one lead at another location in the circuit. The voltmeter tells you what the voltage is between those two points.

Question 15

What is a cell?

Answer 15

A cell is a storage compartment for electricity in a battery, in which it has a specific voltage. For example, in a particular battery, cells may be 1-5 volts. Therefore, you can figure out the number of cells that battery has by dividing the voltage of the battery by 1.5.

Question 16

Electrical current can’t flow without a circuit, and a working circuit must include three components, what are those?

Answer 16

1. A voltage source, such as battery.
2. A load, which is a source of resistance that converts electrical energy into another form of energy (like a light bulb).
3. Conductors, which are necessary to carry the current from point A to point B.

Question 17

What are circuit breakers?

Answer 17

Circuit breakers are designed to break a circuit when too much energy is flowing through an electrical system. The circuit breaker panel in your house is great example. If your washing machine is sucking too much power from the electrical outlet, putting too much of a load on your electrical system, the circuit breaker literally breaks the circuit to interrupt the flow before it can damage all the wiring in your house.

Question 18

What are fuses?

Answer 18

Fuses work the same way. Fuses are thin wires enclosed in a safe insulating material, and they’re just part of a circuit. however, they’re designed to burn up if the current heats up above a certain level. When the fuse disintegrates, the circuit is interrupted and can’t carry any more electricity. Fuses work once only; you have to replace them if one is blown.

Question 19

When it comes to circuit, there are three main types of circuits, what are those?

Answer 19

1. Series circuits have only one path electrical current can take. A break anywhere in the circuit stops the whole operation.
2. Parallel circuits are very common. In this type of circuit, every load is wired along its own path. If a break occurs in one path to one load, the current continues to flow to the other loads. The voltage in parallel circuit remains the same throughout each parallel branch of the circuit, but the current flow can vary across each branch. The total current remains the same.
3. Series-parallel circuits are the most common arrangement. Most houses are wired this way. These circuits are more complicated because they include more components, such as on/off switches and fuses.

Question 20

How do you measure power?

Answer 20

Power is measured in watts. one watt is a very small amount of power. It would require nearly 750 watts to equal 1 horsepower. One kilowatt represents 1,000 watts.

Power (watts) = Voltage (volts) x Current (amperes)

Question 21

Electric currents can produce different effects. These effects are packaged and sold commercially. Describe the effects produced by current and some of their commercial applications.

Answer 21

• Chemical effect: Current produces this effect when it passes through a chemical compound and breaks up that compound. Also called electrolytic decomposition, this phenomenon is used in electroplating, a process used to cover objects with a very thin coating of metal. this effect is used to make less expensive jewelry.
• Heat effect: Conducting electricity causes wires to become heated. Heat develops because the current must overcome the resistance of the wire. This heat energy can be quite obvious or hardly noticeable to touch, depending on the size of the wire and the amount of current. You’ve used this effect to cook dinner if you have an electric stove.
• Magnetic effect: When a wire is introduced into a magnetic field, electricity flows through the wire and creates a magnetic field that repels a magnet. This effect is used to create energy through electromagnetic induction, the basic principle behind the electric generator. If the wire is wrapped around an iron core and a current is sent through the wire, the iron becomes magnetized.
• Psychological effect: Current produces this effect when it passes through your bicep (or any of your muscles, for that matter) and causes the muscle to contract. This effect is used in medicine.

Question 22

What is the difference between (DC) Direct Current and (AC) Alternating current?

Answer 22

A direct current flows in one direction, but an alternating current constantly changes direction in a regular pattern.

Question 23

What is AC/DC?

Answer 23

AC/DC is a combination of direct current and alternating current. Your laptop uses it, a wall-plug phone charger uses it, and some vehicles uses it. AC comes in through the outlet, and the box (the rectifier) between the outlet and the part that plugs into your device transforms it to DC.

Question 24

In electronics, what is frequency? and What is hertz?

Answer 24

Frequency is the number of times an alternating current changes direction per second. Hertz (Hz) is the unit of measurement for frequency. One hertz (Hz) equals one complete cycle per second. In other words, the current makes two complete alternations of direction.

Question 25

Resistance interferes with the flow of current in a circuit. But the flow of current is also impeded by two properties of alternating currents, what are those?

Answer 25

1. **Capacitive reactance (capacitance):** Capacitive reactance is a measure of a capacitor's opposition to alternating current, and it's measured in ohms. Capacitance is the storage of energy that occurs in a nonconductor, and it's measured in farads (F). This property resists any change in voltage in a circuit. 2. **Inductive reactance (inductance):** Inductive reactance, also measure in ohms, is the resistance to a change in the flow of current. Inductance is the property that causes current to increase or decrease even more based on changes in current induced in a circuit. This inductance creates an electromotive force and is measured in henry's (H).

Question 26

Capacitive reactance (capacitance) and inductive reactance (inductance) combine to impede the flow of current. Impedance can become incredibly complex, but in its simplest form, it can be expressed as the ratio of electromotive force to the current (Express in a mathematical expression).

Answer 26

Impedance = Electromotive force/Current

Question 27

Electronic devices often require a specific capacitive or inductive reactance to work. Capacitors are rated in \_\_\_\_\_\_\_, and inductors are rated in \_\_\_\_\_\_\_\_.

Answer 27

Capacitors are rated in microfarads (μF), and inductors are rated in millihenries (mH).

Question 28

Certain electronic circuits are engineered to change alternating current to direct current. What is the process of making this change?

Answer 28

The process of changing alternating current to direct current is called rectification, and the circuits that perform the rectification are called rectifiers. Rectifiers contain semiconductor diodes, a component made of a material with conductivity where between that of a conductor and an insulator. Diodes conduct electricity in only one direction. Rectification also often requires inductors and capacitors. ^{Rectification helps appliances run at cooler temperatures and allows them to run at variable speeds. Devices typically need direct current to run properly. The process of rectification changes the incoming AC to DC. Manufacturers often use diodes, which used to be housed in big, glass vacuum tubes, to rectify current in many appliances and electronic devices.}

Question 29

What is a transistor?

Answer 29

A transistor is a semiconductor (an object that conducts electricity poorly at low temperatures) that controls the flow of electricity in a circuit. It's usually made of germanium or silicon. This electrical device can amplify a signal, which is why it's used in transistor radios.

Question 30

Transistors have many properties, what are those?

Answer 30

1. Unlike rectifier diodes, a transistor doesn't require a vacuum to operate. 2. Transistors are small, require little power, and last a long time. 3. A transistor contains at least three terminals: * The emitter is the voltage output. * The base acts like a gate, and the voltage at the base controls the flow of current through the transistor (therefore the voltage). * The collector is the voltage input.

Question 31

What are block diagrams?

Answer 31

Electronic circuits can be combined to create complex systems, such as those required to operate stereo system. Block diagrams are used to show the various circuits that form a complex system.

Question 32

Name each symbol in electronic circuit diagrams and set forth its function when connected in a circuit.

Answer 32

**Wires:** Wires are used to pass current from one part of the component to another. Wires that are connected to each other are indicated by a dark circle and are called joined wires. Sometimes in complex circuit diagrams, it's necessary to draw wires crossing even though they aren't connected. In this case, the dark circle is omitted, or hump symbol is drawn to make it clear the wires aren't connected — these are called unjointed wires. **Cell:** A cell supplies electrical current. Some call this a battery, but technically a battery is more than one cell. The large terminal (on the left side of the cell image) is positive. **Battery:** A battery is two or more cells. The large terminal is positive. **DC power supply:** A DC power supply provides direct current. Direct current always flows in one direction. **AC power supply:** An AC power supply provides alternating current. Alternating current constantly changes direction at a specific frequency. **Fuse:** A fuse is a safety device that blows (melt) if the current flowing through it exceeds a specified value. **Transformer:** A transformer consists of two coils of wire linked by an iron core. Transformers are used to step up (increase) and step down (decrease) AC voltages. No electrical connection exists between the coils. Energy is transferred between the coils by the magnetic field in the core. **Ground:** A ground is a connection to the Earth. **Transducer:** A transducer is a device that converts energy from one form to another. Here are various types of transducers: * **Lighting lamp:** Converts electrical energy to light, such as in a light bulb or automobile headlight * **Indicator lamp:** Converts electrical energy to light for such uses as a warning light on a car's dashboard. * **Motor:** Converts electrical energy to kinetic energy (motion) * **Heater:** Converts electrical energy to heat. * **Bells and buzzers:** Convert electrical energy to sound. * **Microphone:** Converts sound to electrical energy. * **Earphones and speakers:** Convert electrical energy to sound. **Inductor:** An inductor is a coil of wire that creates a magnetic field when current passes through it. **Switch:** Here are several types of switches: * **Push switch:** A push switch allows current to flow only when the button is pressed, such as in a doorbell. * **Push-to-break switch:** With this switch, the circuit is normally closed (the device is on); the circuit is open (device is off) only when the button is pressed. * **On/off switch:** An on/off switch allows current to flow only when it's in the closed (on) position. * **Two-way switch:** A two-way switch directs the flow of current to one of two routes, according to its position. * **Dual on/off switch:** This type is often used to switch main electricity because it can isolate both the live and neutral connections. * **Relay (relay switch):** A relay is an electrically operated switch that may operate multiple switches at one time. Typically, a small current flowing through a coil sets up a magnetic field, which causes the lever(s) to move, effectively changing the (relay) switch's position(s). As an example, a 5-volt signal from your dashboard turns on your 12-volt headlights through a relay. **Resistor (nonvariable):** There are two different versions of the basic resistor symbol. Resistors restrict the flow of electric current. Resistors are rated in ohms and have a color code on them to indicate their value, tolerance, and sometimes quality. The band code is as follows: * Black is 0 * Brown is 1 * Red is 2 * Orange is 3 * Yellow is 4 * Green is 5 * Blue is 6 * Violet is 7 * Gray is 8 * White is 9 The first and second bands on the resistor are the first two digits in the resistor's value. The next band indicates the multiplier (number of zeros after the first two numbers). So, if the first band is red, the second is yellow, and the third band is orange, the resistor's value is 24,000 ohms, A gold or silver band after the first bands indicates tolerance, and a quality band may follow the tolerance band. **Variable resistor:** Variable resistors also restrict the flow of electric current. There are several symbols in use in circuit diagrams for standard variable and preset variable resistors. Types of variable resistors include the following * **Rheostat:** A type of variable resistor with two contacts, usually to control current; examples of controlling current would be adjusting lamp brightness or adjusting motor speed. * **Potentiometer:** A type f variable resistor with three contacts that's used to control voltage. * **Preset variable resistor:** A device that operates with a small screwdriver or similar tool; it's designed to be set when the circuit is made and then left without further adjustment. **Capacitor:** Capacitor store electric charge. They're used with resistors in timing circuits because it takes time for a capacitor to with charge. They're also used in filter circuits because capacitors easily pass AC (changing voltage) signals but they block DC (constant voltage) signals. Two types of capacitors include the following: * **Polarized capacitors** must be connected the correct way in circuit. * **Variable capacitors** are used most often in radio tuning circuits. **Diode:** Diodes allow electricity to flow in only one direction. The arrow of the circuit symbol shows the direction in which the current can flow. Diodes are the electrical version of a valve, and early diodes were actually called valves. Light-emitting diodes (LEDs) emit light when an electric current passes through them. Specialized diodes, called Zener diodes, do allow current in the opposite direction after a threshold. is met. **Transistor:** Transistors amplify current. For example, they can be used to amplify the small output current from a logic chip so it can operate a lamp, relay, or other high-current device. **Amplifier:** An amplifier isn't actually an electronic component but instead is a complex circuit. The block diagram symbol shows where an amplifier circuit would be connected. Amplifier circuits are used to magnify power, current, or voltage. **Antenna:** An antenna is a device designed to receive and/or transmit radio signals.

Question 33

In electrical terms, phase refers to… differ the phases.

Answer 33

In electrical terms, phase refers to the distribution of a load. A single-phase wire has three wires within the insulation (two hot, or wires and one neutral wire). A phase 2 wire has two live wires, each providing the same voltage but with different peaks and dips in voltage, and one or two neutral wires. A phase 3 wire contains three hot wires (and sometimes a neutral wire), with each AC signal being 120 electrical degrees apart.

Question 34

AC wires that travel between the last protective device (such as circuit breaker) and the load on branch circuits carrying 120, 208, or 240 volts are?

Answer 34

* **Black** for phase 1 * **Red** for phase 2 * **Blue** for phase 3 * **White** if they're neutral * **Green, green with a yellow stripe, or bare wire** if they're ground wires * **Orange** if the wiring system has one phase at a higher voltage than the others.

Question 35

AC wires in 277- or 480- Volt systems are:

Answer 35

* **Brown** for phase 1 * **Orange** for phase 2 * **Yellow** for phase 3 * **Gray** if they are neutral * **Green, with a yellow stripe, or bare wire** if they're ground wires.