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26 Cards in this Set
- Front
- Back
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What are the four basic sections of a power supply?
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Transformer, rectifier, filter, regulator.
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What is the purpose of the rectifier section?
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To change ac to pulsating dc.
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What is the purpose of the filter section?
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To change pulsating dc to pure dc.
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What is the purpose of the regulator section?
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To maintain a constant voltage to the load.
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What is the name of the simplest type of rectifier which uses one diode?
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The half-wave rectifier.
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If the output of a half-wave rectifier is 50-volts peak, what is the average voltage?
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15.9 volts.
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In addition to stepping up or stepping down the input line voltage, what additional purpose does
the transformer serve? |
It isolates the chassis from the power line.
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What is the most basic type of filter?
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The capacitor filter.
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In a capacitor filter, is the capacitor in series or in parallel with the load?
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Parallel.
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Is filtering better at a high frequency or at a low frequency?
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At a high frequency.
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Does a filter circuit increase or decrease the average output voltage?
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At a high frequency.
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What determines the rate of discharge of the capacitor in a filter circuit?
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Value of capacitance and load resistance.
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Does low ripple voltage indicate good or bad filtering?
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Good.
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Is a full-wave rectifier output easier to filter than that of a half-wave rectifier?
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Yes.
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In an LC choke-input filter, what prevents the rapid charging of the capacitor?
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The CEMF of the inductor.
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What is the range of values usually chosen for a choke?
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From 1 to 20 henries.
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If the impedance of the choke is increased, will the ripple amplitude increase or decrease?
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Decrease
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Why is the use of large value capacitors in filter circuits discouraged?
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Expense.
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When is a second RC filter stage used?
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When ripple must be held at an absolute minimum.
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What is the most commonly used filter today?
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LC capacitor-input filter.
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What are the two main disadvantages of an LC capacitor filter?
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Cost and size of the inductor.
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Circuits which maintain constant voltage or current outputs are called dc voltage or dc current
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Regulators.
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The purpose of a voltage regulator is to provide an output voltage with little or no ___.
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Variation.
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The two basic types of voltage regulators are ___ and ___.
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Series and shunt.
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When a series voltage regulator is used to control output voltages, any increase in the input
voltage results in an increase/a decrease (which one) in the resistance of the regulating device. |
An increase.
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A shunt-type voltage regulator is connected in serial/parallel (which one) with the load resistance.
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In parallel.
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