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54 Cards in this Set

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  • Back
What are four basic types of filter circuits?
simple capacitor filter, LC choke-input filter, LC capacitor-input filter. RC capacitor-input filter
What is used as series impedances to oppose the flow of ac?
inductor
What are used as shunt elements to bypass the ac to ground?
capacitors
In low current applications, what can be used in place of inductors?
resistors
How are filter capacitors placed with the load?
in parallel
A high Xc filters better in capacitor filter. (True/False)
False
What characters capacitor must have to obtain a steady dc output?
fast charge time and slow discharge time
Keeping the internal resistance of the power supply as small as possible, will give fast charge time. (True/False)
True
The resistance of the loads as large as possible will give a low discharge time. (True/False)
True
What does one time constant will charge a capacitor to?
63.2%
What does one time constant will discharge a capacitor to?
36.8
A capacitor is considered fully charged after what?
5 RC time constants
What effects will large capacitor have?
Smaller resistance to ac, and longer discharge time
What opposes any change in current?
inductor
What effect does an inductor produces to oppose the change in circuit current?
counterelectromotive force (CEMF)
What is opposition to a change in current at a given frequency called?
inductive reactance
What are both capacitance and inductance measured in?
ohms
How are inductors placed in filter?
in series
The larger the capacitance, the larger the ac voltage developed across the load. (True/False)
True
What is the most basic type of power supply filter?
simple capacitor filter
What filter is used with relatively high output current?
LC choke-input filter
What is the most commonly used filter?
LC capacitor-input filter
What filter is used in high-voltage power supplies for cathode-ray tubes?
RC filters
What filter is used in high power applications as such as those found in radars?
LC choke-input filter
What filters are used when output current is low and the load current is constant,?
RC filter and LC capacitor-input filter
What filter is used primary in power supplies where voltage regulation is important?
LC choke-input filter
In LC choke-input filter what is the filter choke?
L1, input inductor
What is the output filter in LC choke-input filter?
C1, output capacitor
What can hold the output voltage relatively constant at the average value of the voltage?
capacitor
In an LC choke-input filter, what prevents the rapid charging of the capacitor?
CEMF of the inductor
What is the range of values usually chosen for a choke?
from 1 to 20 henries
If the impedance of the choke is increased, will the ripple frequency increase or decrease?
decrease
What is subject to excessive leakage?
capacitor
What is subject to short circuit to the core?
inductor
What may reduces the value of inductance?
shorted turns
What will result excessive peak-rectifier current?
reduced inductance
What may be causes of a no-output condition?
A choke winding is open, or a choke winding shorted to the core
What may cause overheating of the rectifier elements(s) or blown fuses?
a choke winding shorted to the core
What is used to determine capacitance and leakage resistance?
a capacitance analyzer
What is input filter in the RC filter?
capacitor, C1
What is output filter in the RC filter?
capacitor, C2
What does a voltage divider consist of in the RC filter?
R1 and C2
What filter is extremely popular because smaller capacitors can be used for keeping minimum ripple?
RC filter
What holds ripple at an absolute minimum at the RC filter?
a second RC filter stage
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?
input capacitor, C1
What protects capacitor in LC choke-input filter?
inductor
What protects capacitor, C2, in RC filter?
resistor
What may be causes of a no-output in filters?
shorted capacitor or open resistor
An excessive ripple amplitude in the output of the supply may be caused by what?
leaky capacitor or defected resistor
How many resistors are in the LC capacitor-input filter?
two
What acts as an ac voltage divider in the LC capacitor-input filter?
inductor, L1 and capacitor, C2
What is the advantage of the LC capacitor-input filter over the RC filter?
low resistance drops minimal dc voltage across
What are the two main disadvantages of an LC capacitor filter?
expensive and bulky, heavy size
What happens when filters loses its efficiency?
the ripple amplitude increases