Term
| The power source of choice for most of our small appliances (e.g., mobile phones, lamps, portable media players) is ___ ___ and some of our audiologic devices (e.g., sound-level meters, otoscopes, hearing aids) |
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Definition
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| Some sources of power such as rotary electromechanical generators produce voltages that ___ polarity (between negative and positive) periodically over time. The voltage and the associated current alternate between ___ and ___ polarity, increasing from zero to a maximum peak in the positive direction, decreasing to zero and then increasing to a maximum peak in the opposite (negative) direction, and then returning to zero. This kind of electrical current is called ___ ___ |
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Definition
| switch; positive; negative; alternating current (AC) |
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Term
| What kind of current is the main power supply in our homes? |
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Definition
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Term
| What are some audiologic devices that use AC? |
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Definition
| audiometers, acoustic admittance meters, and instrumentation used to measure auditory evoked potentials. |
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Term
| In AC circuits, the ___ of the flow of electric charge changes periodically, so AC and voltage in an AC circuit can be characterized by the four parameters of a sinusoidal wave: ___, ___, ___, and ___. |
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Definition
| polarity; wavelength, time period, frequency, and amplitude |
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Term
| distance between two maxima points or two minima points on a waveform is called one ___ |
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Definition
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Term
| “The time required for one wavelength of alternating current or one cycle of a sinusoidal acoustic wave to pass through a point is called the ___ ___” |
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Definition
| time period (T)-measured in seconds |
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Term
| “number of cycles the current waveform completes in one second and is the inverse of the time period” |
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Definition
| frequency (f) measured in cycles/seconds or Hz |
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Term
| What is the equation for frequency? |
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Definition
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Term
| A good conductor almost travels at the speed of life. What is the equation for the speed of light? |
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Definition
| c = fλ, where c is the speed of light and l is wavelength. |
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Term
| The magnitude of the amplitude of an ideal DC voltage is ___. The magnitude of an AC voltage signal ___ with time. |
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Definition
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Term
| The ________ value is the effective value of a varying voltage or current. It is the equivalent steady DC (constant) value which gives the same effect. For example, a lamp connected to a 6V RMS AC supply will shine with the same brightness when connected to a steady 6V DC supply. |
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Definition
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Term
| In our homes, the power supplied to the power mains is a ___ volt AC sinusoidal waveform with a frequency of 60 Hz. This standard is used mainly in ___ ___ and is governed by “the International Electrotechnical Commission (IEC) |
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Definition
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Term
| “A ___ or a ___ ___ is a rotating vector.” |
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Definition
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Term
| Although we comprehend an AC signal as a sinusoidal waveform, it can also have ___ (e.g., triangular wave, square wave, saw-tooth waveform) that are generated by certain types of digital ___ and have applications in the digital logic design industry |
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Definition
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Term
| The ___ wave is the most widely used in fields such as communications, digital design, signal processing, and audio processing. These waves play an important role in technologies for generating _____ signals in modern audiometers |
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Definition
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Term
| A ___ ___ is a periodic mathematical function that alternates instantaneously between two levels, ideally for the same amount of time. |
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Definition
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Term
“In the square wave shown in Figure 4–3, the amplitude is positive for exactly half the cycle or time period. Therefore, the signal has a ___% duty cycle. If a signal’s amplitude is positive across only one-fourth of its cycle, then the signal has a ___% duty cycle”
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Definition
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Term
| “Unlike a sine wave, a square wave has more than one ___ component” |
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Definition
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Term
| The formula that tells you which sine-wave components are present in the square wave signal and the proportions of these components in the sine-wave signal |
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Definition
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Term
| “Electric power transmission refers to transmission of electricity from the generating ___ into our ___.” |
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Definition
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Term
| Because electrical transmission over long distances leads to ___ ___ by heat dissipation resulting from the resistance of the transmitting wires, the voltage carried by the transmission lines must be ___. With DC electrical transmission, this boost was accomplished using complex and expensive spinning rotary ___ (a hybrid of an AC motor and a DC generator) at regular points along the transmission line. |
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Definition
| power losses; boosted; converters |
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Term
| “Today’s AC power generators are ___-phase alternators. An alternator is an electromechanical device that converts ___ energy into ___ energy. It consists of a rotating magnet called a ___ that spins inside a coil of wires wound around a cylindrical iron core called a ___ (Figure 4–7). When the magnetic field changes due to the rotation of the ___ with respect to the wires on the stator, alternating current is induced in the coiled wires.” |
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Definition
| three; mechanical; electrical; rotor; stator; magnet |
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Term
What is this diagram showing?
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Definition
| Current flow in a simple resistive DC circuit is shown in A and a simple AC circuit is shown in B. In B the solid arrows show the direction of current flow in one direction during one-half of the cycle and the dotted lines show the direction of current flow in the opposite direction during the other half of the cycle |
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Term
| “___ is the measure of the ability of an object to store an electric charge similar to the spring’s ability to store mechanical (potential) energy” |
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Definition
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Term
| What is the unit of capacitance? |
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Definition
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Term
| Capacitance also can be defined as the ratio of the ___ on one conducting plate to the ____ ___ between the two plates. If these two charged plates are connected to a resistor then they will act like a ___, supplying electrical energy in the form of current to the resistor until they discharge completely. In summary, this setup of two conducting plates separated by a dielectric material forms a ___ |
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Definition
| charge; potential difference; battery; capacitor |
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Term
-A ___ is a passive component used to insert capacitance into a circuit.
-“A capacitor stores electrical energy in the form of an ___ ___.” |
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Definition
| capacitor; electric field |
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Term
| “The lead wires from each plate are connected to create a ___. An ideal capacitor stores the charge accumulated on it without ___ any energy in the form of a counter-EMF (electromotive force) to resist charging by the connected source.” |
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Definition
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