ASVAB Electronics Exam 159 Questions with Verified Answers,100% CORRECT

ASVAB Electronics Exam 159 Questions with Verified Answers Electricity - CORRECT ANSWER General term for the variety of phenomena resulting from the presence and flow of electric current Volts Amperes (amps) Ohms ...

ASVAB Electronics Exam 159 Questions with Verified Answers Electricity - CORRECT ANSWER General term for the variety of phenomena resulting from the presence and flow of electric current Volts Amperes (amps) Ohms - CORRECT ANSWER 3 ways Electricity is measured Volts - CORRECT ANSWER Measure the difference of potential between 2 points Amperes (amps) - CORRECT ANSWER Measure the number of electrons that move past a specific point in 1 second (i.e. electrical currents) Ohms - CORRECT ANSWER Measure resistance, including anything that could limit the flow of electrons Current - CORRECT ANSWER Electrical ___ occurs when electrons move from one place to another. Conductors (e.g. copper, silver, water) - CORRECT ANSWER A substance, body, or device that conducts electricity; allows the electrons to move freely. Insulators (e.g. rubber, wood) - CORRECT ANSWER A material of such low conductivity that does not easily allow the flow of electrical current to pass through it; discourages electrical current Watt - CORRECT ANSWER This measures power, the rate at which electrical energy is consumed or transformed into another type of energy, such as light or heat Power - CORRECT ANSWER The rate at which electrical energy is consumed or transformed into another type of energy, such as light or heat Watt-hour - CORRECT ANSWER This is the amount of energy used in 1 hour at a rate of 1 watt. Kilowatt-hour - CORRECT ANSWER The amount of energy used in 1 hour at a rate of 1,000 watts(i.e.1-kilowatt) True - CORRECT ANSWER True or False Most electricity is measured in kilowatt-hours Wattage x Time (expressed in hours) - CORRECT ANSWER To find watt-hours multiply ___ by ___. 10 kilowatt-hours - CORRECT ANSWER How many kilowatt-hours is enough energy to run a 10,000-watt speaker system for 1 hour? 2 hours - CORRECT ANSWER 10 kilowatt-hours is enough energy to run a 5,000-watt air conditioner for how long? 10 hours - CORRECT ANSWER 10 kilowatt-hours is enough energy to run a 1,000-watt waffle iron for how long? Circuit - CORRECT ANSWER The path of an electrical current Open - CORRECT ANSWER When there is literally an open space in the circuit that prohibits current from flowing Short - CORRECT ANSWER When the open space of a circuit has been closed to allow current to flow Voltage - CORRECT ANSWER The difference of the pressure between 2 points in a circuit (sometimes called voltage drop or difference of potential) True - CORRECT ANSWER True or False To see what the voltage is anywhere in a circuit, you have to compare the voltage at that point to ground Ground (e.g. base of a lamp, chassis of a car) - CORRECT ANSWER Any part of a circuit (or other object that has electricity running through it) that measures 0 volts Voltmeter or multimeter - CORRECT ANSWER Measures voltage in a circuit Voltmeter - CORRECT ANSWER An instrument used for measuring electrical potential difference between two points in an electric circuit (i.e. voltage) A voltmeter has 2 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 2 points. - CORRECT ANSWER How to use a voltmeter: Cell - CORRECT ANSWER A storage compartment for electricity in a battery that has a specific voltage. True - CORRECT ANSWER True or False You can figure out the number of cells a battery has by dividing the voltage of the battery by the volts. Electrical current - CORRECT ANSWER The flow (rate of flow) of electrons in a conductor coulombs (C), which measure charge. - CORRECT ANSWER Current flow can be expressed in terms of ___. Coulomb - CORRECT ANSWER The amount of electricity provided by a current of 1 ampere flowing for 1 second. True - CORRECT ANSWER True or False If 1 coulomb (about 6,241,500,000,000,000,000 electrons) flows past a specified point in 1 second, that's a flow rate of 1 ampere (amp, abbreviated A). Ammeters - CORRECT ANSWER Measure the flow of current through a circuit True - CORRECT ANSWER True or False Typically current is tiny, so small that it's measured in milliamperes; 1 milliampere is one-thousandth of an ampere. Circuit breaker - CORRECT ANSWER A device that automatically interrupts the electrical current. True or False - CORRECT ANSWER True or False Sometimes a circuit must be opened in order to add or remove resistance. In other words, the flow of electricity must be interrupted in order to physically change the resistance. Rheostat - CORRECT ANSWER A device which can vary the resistance without opening the circuit - the electrical device can continue to work even as the resistance is altered A dimmer switch on a light; you increase the amount of resistance to dim the light and decrease the resistance to brighten the light - CORRECT ANSWER Example of a rheostat Ohms (Ω) - CORRECT ANSWER The SI unit of electrical resistance; measures the amount of resistance that interferes with the flow Ohmmeter - CORRECT ANSWER Device that measures the amount of resistance that interferes with the flow The amount of voltage (measured in volts) The resistance to the current (measured in ohms) The amount of current (measured in amps) - CORRECT ANSWER The 3 influences that are present when current flows through a wire The current in a circuit is directly proportional to the applied voltage and inversely proportional to the circuit resistance. - CORRECT ANSWER What is Ohm's law I - CORRECT ANSWER Abbreviation for current E - CORRECT ANSWER Abbreviation for voltage R - CORRECT ANSWER Abbreviation for resistance Current (amperes) = Voltage(volts)/Resistance(ohms) OR I = E / R - CORRECT ANSWER Formula to solve for Current (Ohm's law) Voltage = Current x Resistance OR E=IR - CORRECT ANSWER Formula to solve for Voltage (Ohm's law) Resistance = Voltage/Current OR R = E / I - CORRECT ANSWER Formula to solve for Resistance (Ohm's law) Watts - CORRECT ANSWER Unit of power in the International System of Units (SI) 750 watts - CORRECT ANSWER How many watts are to 1 horsepower True or False - CORRECT ANSWER One kilowatt represents 1,000 watts By multiplying the number of kilowatts (kW) required by the number of hours of use. (e.g. if you use a 40-watt light bulb 5 hours a day, you've used 200 watt-hours, or 0.2 killowatt-hours of electrical energy) - CORRECT ANSWER How are kilowatt-hours determined? Least - CORRECT ANSWER Electricity follows the path of ___ resistance. Conventional Current - CORRECT ANSWER The vacancies left by electrical particles "moving" from the positive (+) terminal to the negative (-) terminal of a battery. (in regards to electrical flow of current) True - CORRECT ANSWER True or False The military teaches current flow based on the flow of the electrons, and electrons, no matter how you look at it, flow from the negative terminal to the positive terminal Short circuit - CORRECT ANSWER This occurs when any wire accidentally crosses over another wire, causing the electricity to bypass the rest of the circuit and not follow the intended path Chemical Effect Heat Effect Magnetic Effect Physiological Effect - CORRECT ANSWER 4 effects produced by current and some of their commercial applications Chemical Effect - CORRECT ANSWER Current produces this effect when it passes through a chemical compound and breaks that compound up. (Also called Electrolytic Decomposition, this phenomenon is used in Electroplating) Electroplating - CORRECT ANSWER A process used to cover objects with a very thin coating of metal. (chemical effect) Heat Effect - CORRECT ANSWER 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 Magnetic Effect - CORRECT ANSWER 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. If the wire is wrapped around an iron core and a current is sent through the wire, the iron become magnetized. Electromagnetic Induction - CORRECT ANSWER The production of electric current across a conductor moving through a magnetic field. It underlies the operation of generators, transformers, etc. Physiological Effect - CORRECT ANSWER Current produces this effect when it passes through your bicep (or any other muscle) and causes the muscle to contract. This effect is used in medicine. Direct Current (DC) - CORRECT ANSWER Current that only and always flows in one direction Alternating Current (AC) - CORRECT ANSWER Current that constantly changes direction in a regular patter AC - CORRECT ANSWER Most electricity comes in the form of __. Alternating Current - CORRECT ANSWER Higher voltages are easier to obtain with ___ current. Frequency - CORRECT ANSWER The number of times a current completes 2 alternations of direction per second Hertz (Hz) - CORRECT ANSWER The unit of measurement for frequency True - CORRECT ANSWER True or False One hertz (Hz) equals one complete cycle per second. In other words, the current makes two complete alternations of direction. 60 Hz - CORRECT ANSWER The Alternating Current (AC) in your house probably completes 60 alternating cycles per second. Therefore, the AC in your house has a frequency of ___ Hz. 1000 Hertz (Hz) - CORRECT ANSWER 1 kilohertz (kHz) = ___ Hz. 1 million Hertz (Hz) - CORRECT ANSWER 1 megahertz (MHz) = ___ Hz. 1 billion Hertz (Hz) - CORRECT ANSWER 1 gigahertz (GHz) = ___ Hz. Capacitive reactance (capacitance) Inductive reactance (inductance) - CORRECT ANSWER 2 properties of alternating currents that impede the flow of current Capacitive reactance (capacitance) - CORRECT ANSWER The storage of energy that occurs in a nonconductor. This property resists any change in voltage in a circuit. Inductive reactance (inductance) - CORRECT ANSWER The property that causes an electromotive force (another way of saying voltage) to be induced in a circuit. Impedance = Electromotive force / Current - CORRECT ANSWER Formula for Impedance Capacitors and Inductors - CORRECT ANSWER Devices used in circuits to provide the type of reactance needed. Microfarad (μF) - CORRECT ANSWER Capacitors are rated in ___. Millihenries (mH) - CORRECT ANSWER Inductors are rated in ___. Rectification - CORRECT ANSWER The process of making certain electronic circuits change alternating current to direct current. (i.e. changes incoming AC to DC) Rectifiers - CORRECT ANSWER The circuits that perform rectification Semiconductor Diodes - CORRECT ANSWER Found in rectifiers; a component made of a material with conductivity somewhere between that of a conductor and an insulator Diodes - CORRECT ANSWER These conduct electricity in only one direction. Inductors and Capacitors - CORRECT ANSWER Rectification often requires ___ and ___. Cooler Variable - CORRECT ANSWER Rectification helps appliances run at ___ temperatures and allows them to run at ___ speeds. Direct - CORRECT ANSWER Devices typically need ___ current to run properly. Semiconductor - CORRECT ANSWER An object that conducts electricity poorly at low temperatures. Transistor - CORRECT ANSWER A semiconductor that controls the flow of electricity in a circuit. Usually made of germanium or silicon. This electrical device can amplify a signal. True - CORRECT ANSWER True or False Transistors are small, require little power, and last a long time Emitter Base Collector - CORRECT ANSWER 3 terminals a transistor contains Emitter - CORRECT ANSWER The voltage output (transistor) Base - CORRECT ANSWER This acts like a gate, and the voltage at the base controls the flow of current through the transistor (and therefore the voltage) Collector - CORRECT ANSWER The voltage input (transistor) Block diagrams - CORRECT ANSWER Used to show the various combined circuits that form a complex system Wires - CORRECT ANSWER Used to pass current from one part of the component to another Joined wires - CORRECT ANSWER Wires that are connected to each other and are indicated by a dark circle in diagrams Unjoined wires - CORRECT ANSWER Wires that are not connected; in circuit diagrams, it is necessary to draw wires crossing even though they aren't connected, this is indicated by a hump symbol Cell - CORRECT ANSWER This supplies electrical current. Battery - CORRECT ANSWER Has 2 or more cells. The large terminal is positive DC Power Supply - CORRECT ANSWER This provides direct current; direct current always flows in 1 direction AC Power Supply - CORRECT ANSWER This provides alternating current; alternating current constantly changes direction at a specific frequency Fuse - CORRECT ANSWER A safety device that blows (melts) if the current flowing through it exceeds a specified value Transformer - CORRECT ANSWER Consists of 2 coils of wire linked by an iron core. These 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 - CORRECT ANSWER A connection to the earth Transducer - CORRECT ANSWER A device that converts energy from one form to another Lighting lamp Indicator lamp Motor Heater Bells & Buzzers Michrophone Earphones & Speakers - CORRECT ANSWER Examples of Transducers Lighting lamp - CORRECT ANSWER Converts electrical energy to light. e.g. light bulb, automobile headlight Indicator lamp - CORRECT ANSWER Converts electrical energy to light for such uses as a warning light on a car's dashboard Motor - CORRECT ANSWER Converts electrical energy to kinetic energy (motion) Heater - CORRECT ANSWER Converts electrical energy to heat Bells and Buzzers - CORRECT ANSWER Convert electrical energy to sound Microphone - CORRECT ANSWER Converts sound to electrical energy Earphones ans speakers - CORRECT ANSWER Convert electrical energy to sound Inductor - CORRECT ANSWER A coil of wire hat creates a magnetic field when current passes through it Push Push-to-break On/off Two-way Dual on/off Relay - CORRECT ANSWER Types of switches Push switch - CORRECT ANSWER A switch that allows current to flow only when the button is pressed e.g. doorbell Push-to-break switch - CORRECT ANSWER With this switch, the circuit is normally closed (the device is on), and the circuit is open (device is off) only when the button is pressed On/off switch - CORRECT ANSWER This switch allows current to flow only when it's in the closed (on) position Two-way switch - CORRECT ANSWER This switch directs the flow of current to one of two routes, according to its position Dual on/off switch - CORRECT ANSWER This type of switch is often used to switch the main electricity because it can isolate both the live and neutral connections Relay (relay switch) - CORRECT ANSWER An electrically operated switch that may operate multiple switches at one time. 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) Resistor (nonvariable) - CORRECT ANSWER Restrict the flow of electric current. True - CORRECT ANSWER True or False Resistors are rated in ohms and have a color code on them to indicate their value, tolerance, and sometimes quality. 0 - CORRECT ANSWER Black is __. (band code) 1 - CORRECT ANSWER Brown is __. (band code) 2 - CORRECT ANSWER Red is __. (band code) 3 - CORRECT ANSWER Orange is __. (band code) 4 - CORRECT ANSWER Yellow is __. (band code) 5 - CORRECT ANSWER Green is __. (band code) 6 - CORRECT ANSWER Blue is __. (band code) 7 - CORRECT ANSWER Violet is __. (band code) 8 - CORRECT ANSWER Gray is __. (band code) 9 - CORRECT ANSWER White is __. (band code) First Second - CORRECT ANSWER The ___ and ___ bands on the resistor are the first 2 digits in the resistor's value. Third - CORRECT ANSWER The ___ band indicates the multiplier (number of zeros after the first two numbers). 24000 ohms - CORRECT ANSWER If the first band is red, the second is yellow, and the third band is orange, the resistor's value is ___ ohms. True - CORRECT ANSWER True or False A gold or silver band after the first bands indicates tolerance, and a quality band may follow the tolerance band. Variable resistor - CORRECT ANSWER Restrict the flow of electric current. Rheostat Potentiometer Preset variable resistor - CORRECT ANSWER Types of variable resistors Rheostat - CORRECT ANSWER Type of variable resistor with 2 contacts, usually used to control current. e.g. of controlling current = adjusting lamp brightness or adjusting motor speed Potentiometer - CORRECT ANSWER A type of variable resistor with three contacts that's used to control voltage Preset variable resistor - CORRECT ANSWER 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 - CORRECT ANSWER Store electric charge. They're used with resistors in timing circuits because it takes time for a ___ to fill with charge. They're also used in filter circuits because ___s easily pass AC signals but they block DC signals Polarized capacitors Variable capacitors - CORRECT ANSWER 2 types of capacitors Variable capacitors - CORRECT ANSWER Capacitor used most often in radio tuning circuits Diode - CORRECT ANSWER Allow electricity to flow in only one direction. The arrow of the circuit symbol shows the direction in which the current can flow. Light-emitting diodes (LEDs) - CORRECT ANSWER Emit light when an electric current passes through them Specialized diodes i.e. Zener diodes - CORRECT ANSWER Allow current in the opposite direction after a threshold is met Transistor - CORRECT ANSWER Amplify current. e.g. 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 - CORRECT ANSWER A complex circuit. Used to magnify power, current, or voltage Antenna - CORRECT ANSWER A device designed to receive and/or transmit radio signals Circuit diagrams - CORRECT ANSWER Show how electronic components are connected together Amperes (amps) - CORRECT ANSWER Unit of measure for current Volts - CORRECT ANSWER Unit of measure for voltage Ohms - CORRECT ANSWER Unit of measure for resistance Watts - CORRECT ANSWER Unit of measure for power Watt-hours - CORRECT ANSWER Unit of measure for energy