ASVAB Electronics Information – Flashcards
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Zener diode, which is available in a variety of voltages.
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What special type of diode is commonly used to regulate voltage?
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Voltage. It is the pressure of the current.
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Electromotive force is another way of saying
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Li-Ion battries. Much more so than Nickel Metal Hydride [NiMH] batteries.
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A primary advantage of using a Li-Ion battery instead o a NiMH battery in your cell-phone is:
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Base, emitter, and collector.
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Transistors contain at least three terminals called the:
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Two three-way switches.
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To control a light fixture from two different wall switches, you should use:
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Crystal amplifier.
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A transistor is also called a:
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Should be connected in series.
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To decrease capacitance, capacitors:
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2,500 ohms. K = one kilo or 1,000.
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A resistor marked 2.5K ohms has the value of:
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Voltage [V] = Current [I] x Resistance [R]
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Ohm's law states:
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Iron. It's easily magnetized and demagnetized, so it works well for this device.
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An electromagnetic-induction device usually has which of the following materials in its core?
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A bridge rectifier [aka full wave rectifier] contains 4 diodes. Rectifiers convert AC to DC current by only allowing it to flow one way.
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How many diodes should you expect to find in a bridge rectifier?
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Hertz [Hz]. The number of times AC changes direction in one second is known as frequency, which is measured in Hz.
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Another name for cycles per second is:
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SIM stands for Subscriber Identity Module. The card contains information such as your phone number, billing information, and address book. It makes switching phones much easier.
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Newer cell phones contain a removable memory card, which is often called a:
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Voltage [electric potential], ohms [resistance], and amperes [current] are always present when current flows through a wire.
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When current flows through a wire, the following influences are present:
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Inductors, which are rated in millihenries.
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Millihenries are related to:
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100,000 Megahertz [MHz]
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Radar can operate at frequencies as high as:
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Radio waves travel at the speed of light. The speed of sound is much slower.
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Radio waves travel:
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Rectification is the process of changing AC to DC.
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Changing alternating current to direct current is called:
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Insulated fittings replace soldering wires together.
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Insulated fittings can be used to splice wires, thus eliminating the need for:
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A battery symbol.
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The circuit symbol of six vertical lines of alternating lengths that do not touch in s circuit is:
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The Ohm symbol.
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The circuit symbol of a nearly completed circle, which looks sort of like a horseshoe at the ends is:
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There are 9 wires in serial cables used on computers. This is true, even if the cable has a 25-pin connector. Serial cables are often used to connect computers to perpetual devices.
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How many wires do serial cables used on computers have?
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Connecting capacitors in parallel produces the most capacitance.
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To produce greater storage of electrons and more capacitance, capacitors should:
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Power = Current x Voltage or Current = Power/Voltage. Which means, 60 / 120 = 0.5 ampere.
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A light bulb is 60 watts. Operated at 120 volts, how much current does it draw?
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The larger the number, the smaller the diameter of the wire. Thus, a number-12 is smaller than a number-6.
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A number-12 wire, compared to a number-6 wire:
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Because fuses are designed to prevent current overload at a specific level, a fuse with a high rating may not work properly for a lower level circuit.
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A fuse with a higher-than-required rating used in an electrical circuit:
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Whitish or natural colored.
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Neutral wire is always:
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Wattmeter, because electrical power is measured in watts.
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To measure electrical power, you would use a:
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The bulb will burn dimmer and last longer because its full potential isn't being used.
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If you operate an incandescent light bulb at less than its rated voltage:
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A cell is equal to 1.5 volts, so 9 volts / 1.5 volts = 6 cells.
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A 9-volt transistor contains:
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Live wires are black.
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The hot wire is always:
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A motherboard is the physical arrangement in a computer that contains the computers basic circuitry and components. It is 12 inches wide.
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How wide is the full AT motherboard?
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An on-off switch in the open position. It allows current to flow only when it's in the closed (on) position.
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The circuit symbol of two circles, one of which has a rod with the potential of connecting to the other circle.
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Determine the wattage that could cause the circuit breaker to trip with this formula: Watts = Amperes x Volts or 25 x 120 = 3,000 watts.
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If a 120-volt current is protected by a 25-amp circuit breaker, what's the largest number of watts an appliance can safely use?
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A rheostat, which is the type of variable resister that is used to control voltage.
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The circuit symbol of a rectangle with a lined arrow pointing towards the center of it is:
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It's the symbol for ground.
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The circuit symbol towards the end of the circuit that looks like an upside down triangle made up of lines of varying lengths.
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Larger wires require less electrical pressure or voltage to run current.
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Two electrical wires run to a machine. One wire is 6mm thick, and the other is 3mm thick. For the two wires to carry the same current, the larger wire:
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Rotor bars are found only on AC induction motors, not DC motors.
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Which of the following isn't a component of a DC motor?
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The ability of a current to contract muscles is called the physiological effect.
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A current passed through a muscle in the human body causes the muscle to contract. This is known as:
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In a closed circuit, one terminal is always positive, and the other is always negative.
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In a closed electrical circuit:
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Root Mean Square is the peak value of voltage multiplied by 0.707 (or sine 45).
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What does RMS stand for?
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The symbol is a fuse, which is designed to "blow" or melt if the current flowing through it exceeds a certain value.
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The circuit symbol of a rectangle with a wire line passing straight through its horizontal middle is:
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NTSC stands for National Television Standards Committee. The system is also used in Japan. PAL and SECAM are used in other countries.
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The television broadcast standard used in the United States is:
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The symbol is a lamp, which is a transducer that converts electrical energy to light.
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The symbol of a circle, with a slightly 'humped' wire going through its center:
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Conventional circuit breaker handles have four positions: on, off, trip, and reset. When tripped, the handle moves to the middle position.
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When a circuit breaker trips, in what position will you find the operating handle?
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The smaller the wire, the larger the number. So 12 AWG would be the smallest.
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Which wire is smallest?
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The symbol for a transformer. Transformers are used to step up [increase] and step down [decrease] AC voltages.
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The circuit symbol of two squiggly-dos on either sides of two vertical lines is actually:
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An example of a series circuit would be a string Christmas lights. If you break the circuit's path at any point, electricity will stop flowing and they will not work. Thus, there is only one path of flow.
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How many paths of electrical flow can be found in a series circuit?
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I (current/amperes) = Power (watts) / Effort (volts). In this case I = 1200 / 120 = 10 amperes.
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A microwave is rated at 1,200 watts. At 120 volts, how much current does it draw?
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Potential equals voltage; low potential is anything less than 600 watts.
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Electricians use the term "low potential" to refer to:
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Glass is an insulator. Other insulators are plastics, paper, and rubber.
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Which of the following isn't a conductor of electricity?
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Ground wires are always green.
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The ground wire is always:
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200 volts. Ohm's law states that V = IR. Thus, V = 10 x 20 = 200 volts.
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To cause a current of 10 amperes to flow through 20-ohms of resistance, the voltage needed is:
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Silver is a better conductor, but much more expensive.
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Silver is a better conductor than copper. But copper is more often used because of:
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Oscillators produce high-frequency AC.
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Electronic circuits that produce high-frequency AC are called:
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When DC is applied to an AC appliance, the amount of resistance is less, so more current flows through the wire and heat builds up.
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If you plug an appliance designed for AC into a DC power source, the appliance:
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