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54 Cards in this Set
- Front
- Back
A capacitor is constructed by separating two metal conductors called——— with an insulating material called a——— |
Plates, Dielectric |
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Two conductive plates separated by an insulating dielectric is the description of a——- |
Capacitor
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Increasing surface area of the plate will cause the capacitance of a capacitor to? |
Increase |
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In some capacitors there is a small amount of current that flows from one plate, through the dielectric material to the other plate. This current is called? |
Leakage |
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In a capacitor, the amount of dielectric stress is proportional to? |
The voltage difference between the plates |
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In a capacitor, the voltage difference between the plates controls the? |
Amount of dielectric stress |
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Energy in a capacitor is stored as a? |
Electrostatic charge |
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The insulating material between the plates is rated by a value call the? |
Dielectric constant |
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The insulating material between the plates is rated by a value call the? |
Dielectric constant |
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The unit for capacitance is? |
Farad |
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The farad is the unit of? |
Capacitance |
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Two capacitors, a 20uF and a 30uf, are connected in parallel. The total capacitance is? |
50uf |
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Three capacitors, a 12uf, a 20uF, and a 30uf are connected in series. The total capacitance is? |
62uf |
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Two capacitors, a 12uf and a 30uf are connected in series. Total capacitance is? |
12uf |
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Three capacitors, a 12uf, a 20uF and a 30uf are connected in series. Total capacitance is? |
6uf |
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Capacitors charge and discharge at a ——- rate |
Exponential |
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When a capacitor and resistor are connected in series, the time required to charge and discharge the capacitor depends on what is call the? |
RC time constant |
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When a capacitor and resistor are connected in series is takes—— time constants for the charge to change completely |
5 |
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A 100uf capacitor and a 3.6kohm resistor are connected in series. How long will it take for the capacitor to change its charge completely. |
1.8s |
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Nonpolarized capacitors can be used with what type of voltage? |
Both A/C and D/C |
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Polarized capacitors can be used with what type of voltage? |
D/C only |
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Polarized capacitors are also known as ——— capacitors |
Electrolytic |
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Variable capacitors normally have a dielectric of? |
Air |
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The JAN standard is used to mark a capacitor intended for? |
Military |
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A HIPOT is a test set used to test capacitor? |
Dielectric |
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Since a capacitor is two conductors separated by an insulator, ——— cannot flow but ——— will appear to flow |
DC, AC |
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The opposition to current flow presented by a capacitor is called? |
Capacitive reactance |
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The unit of capacitive reactance is? |
Ohm |
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The symbol for capacitive reactance is? |
Xc |
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A 35uf capacitor is connected to a 60hz, 120v supply. What is the Xc of the capacitor? |
75.79 |
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A capacitor is connected to a 240v supply. An ammeter indicates 3A. What is the capacitive reactance of the capacitor? |
720ohm |
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In a cct containing a capacitor, the impressed voltage is ——— with the applied voltage. |
180degree out of phase |
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In a capacitor, the current —— the applied voltage. |
Leads |
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In a capacitor, the current —— the applied voltage by —— |
Lead by 90degrees |
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The power in a capacitor is reactive power. The unit for reactive power is? |
VAR |
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The quality of a capacitor is found by Q= |
R/Xc |
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The voltage rating of a capacitor should never? |
Be exceeded |
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The capacitive reactance of a capacitor is ——— proportional to the frequency of the applied voltage |
Inversely |
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A 10ft capacitor has 2652ohms of reactance at 60hz. How much is the reactance at 400hz? |
397.88ohms |
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What is the reactance of a 15uf capacitor when the applied frequency is 2.5Khz? |
4.24ohma |
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What is the reactance of a 25uf capacitor when the applied frequency is 400hz? |
15.98ohms |
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What is the reactance of a 25uf capacitor when the applied frequency is 400hz? |
15.98ohms |
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Two capacitors a 20uF, and a 30uf, are connected is series to a 60hz source. The total capacitive reactance is? |
221.04 |
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Two capacitors, a 20uF and a 30uf are connected in series to a 400hz source. The total capacitive reactance is? |
33.16 |
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Three capacitors a 12uf, a 20uF and a 30uf are connected in series to a 60hz source. The total Xc is? |
442.09 |
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Three capacitors, a 12uf, a 20uF and a 30uf are connected in series to a 400hz source. Total Xc is? |
66.32 |
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*important* Two capacitors, a 20uF and a 30uf are connected in parallel to a 60hz source. Total capacitive reactance is? |
53.05ohms |
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Two capacitors, a 20uF, and a 30uf are connected on parallel to a 400hz source. Total capacitive reactance is? |
7.96 |
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Three capacitors, a 12uf, a 20uF and a 30uf are connected in parallel to a 60hz source. Total Xc is? |
442.09 |
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Three capacitors. A 12uf, a 20uF and a 30uf are connected in parallel to a 400hz source. Total Xc is? |
6.42ohms |
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In a series RC cct, total impedance is the —— sum of the resistances and reactances in a cct |
Vector |
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Dividing a cct’s total applied voltage by the total impedance results in total? |
Current |
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In a series RC cct, Et=240v, R=40ohms and Xc=30ohms. What is Er |
192v |
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In a series RC cct, Et=240v, R=500ohms and Xc=500ohms. What is the tp? |
57.62w |