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54 Cards in this Set
- Front
- Back
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What are four basic types of filter circuits?
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simple capacitor filter, LC choke-input filter, LC capacitor-input filter. RC capacitor-input filter
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What is used as series impedances to oppose the flow of ac?
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inductor
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What are used as shunt elements to bypass the ac to ground?
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capacitors
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In low current applications, what can be used in place of inductors?
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resistors
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How are filter capacitors placed with the load?
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in parallel
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A high Xc filters better in capacitor filter. (True/False)
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False
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What characters capacitor must have to obtain a steady dc output?
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fast charge time and slow discharge time
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Keeping the internal resistance of the power supply as small as possible, will give fast charge time. (True/False)
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True
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The resistance of the loads as large as possible will give a low discharge time. (True/False)
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True
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What does one time constant will charge a capacitor to?
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63.2%
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What does one time constant will discharge a capacitor to?
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36.8
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A capacitor is considered fully charged after what?
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5 RC time constants
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What effects will large capacitor have?
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Smaller resistance to ac, and longer discharge time
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What opposes any change in current?
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inductor
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What effect does an inductor produces to oppose the change in circuit current?
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counterelectromotive force (CEMF)
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What is opposition to a change in current at a given frequency called?
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inductive reactance
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What are both capacitance and inductance measured in?
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ohms
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How are inductors placed in filter?
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in series
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The larger the capacitance, the larger the ac voltage developed across the load. (True/False)
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True
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What is the most basic type of power supply filter?
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simple capacitor filter
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What filter is used with relatively high output current?
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LC choke-input filter
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What is the most commonly used filter?
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LC capacitor-input filter
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What filter is used in high-voltage power supplies for cathode-ray tubes?
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RC filters
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What filter is used in high power applications as such as those found in radars?
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LC choke-input filter
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What filters are used when output current is low and the load current is constant,?
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RC filter and LC capacitor-input filter
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What filter is used primary in power supplies where voltage regulation is important?
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LC choke-input filter
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In LC choke-input filter what is the filter choke?
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L1, input inductor
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What is the output filter in LC choke-input filter?
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C1, output capacitor
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What can hold the output voltage relatively constant at the average value of the voltage?
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capacitor
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In an LC choke-input filter, what prevents the rapid charging of the capacitor?
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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 frequency increase or decrease?
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decrease
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What is subject to excessive leakage?
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capacitor
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What is subject to short circuit to the core?
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inductor
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What may reduces the value of inductance?
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shorted turns
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What will result excessive peak-rectifier current?
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reduced inductance
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What may be causes of a no-output condition?
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A choke winding is open, or a choke winding shorted to the core
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What may cause overheating of the rectifier elements(s) or blown fuses?
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a choke winding shorted to the core
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What is used to determine capacitance and leakage resistance?
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a capacitance analyzer
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What is input filter in the RC filter?
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capacitor, C1
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What is output filter in the RC filter?
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capacitor, C2
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What does a voltage divider consist of in the RC filter?
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R1 and C2
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What filter is extremely popular because smaller capacitors can be used for keeping minimum ripple?
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RC filter
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What holds ripple at an absolute minimum at the RC filter?
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a second RC filter stage
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What capacitor has the greatest pulsating voltage applied to it and is the most susceptible to voltage surges when there are two capacitors in the filters?
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input capacitor, C1
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What protects capacitor in LC choke-input filter?
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inductor
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What protects capacitor, C2, in RC filter?
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resistor
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What may be causes of a no-output in filters?
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shorted capacitor or open resistor
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An excessive ripple amplitude in the output of the supply may be caused by what?
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leaky capacitor or defected resistor
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How many resistors are in the LC capacitor-input filter?
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two
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What acts as an ac voltage divider in the LC capacitor-input filter?
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inductor, L1 and capacitor, C2
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What is the advantage of the LC capacitor-input filter over the RC filter?
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low resistance drops minimal dc voltage across
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What are the two main disadvantages of an LC capacitor filter?
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expensive and bulky, heavy size
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What happens when filters loses its efficiency?
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the ripple amplitude increases
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