793196
Description
Flashcards by pete.c.diaz, updated more than 1 year ago
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Created by pete.c.diaz
almost 10 years ago
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| Question | Answer |
| How is ac current related to ac voltage in a purely capacitive circuit? | AC current leads ac voltage. |
| The material used between the plates of a capacitor is called its: | dielectric material |
| When is a capacitor fully charged? | When the current through the capacitor is the same as when the capacitor is discharged. |
| A capacitor is constructed of two parallel: | conductors |
| A capacitor stores energy within a dielectric between the conducting plates in the form of: | an electric field |
| As a capacitor is being charged, current flowing into the capacitor will: | decrease |
| As a capacitor is being charged, the voltage across its terminals will: | increase |
| When a circuit consists of a capacitor and a resistor in series with a voltage source, and the voltage across the resistor is zero, than the capacitor is: | fully discharge |
| If a charge capacitor is is disconnected from a circuit, it will: | leak the charge |
| The strength of an electric field at a given point is proportional to the potential difference on the plates and inversely proportional to the: | plate separation |
| The strength of an electric field at a given point is proportional to the potential difference on the plates an inversely proportional to the: | plate seperation |
| For a given charge difference, electrostatic field strength varies according to: | plate area |
| What is the value of a capacitor that can store two coulombs of charge when 500 volts is applied across its plates? | 4,000 uF Q/VxC |
| * If the dielectric constant of a capacitor is decreased, than its capacitance will: | decrease * |
| Most older types of paper capacitors have been replaced by which type of construction? | plastic film |
| Capacitor value markings are usually: * | Alphanumeric * |
| After which time constant can a capacitor be considered to be fully charged? | fifth |
| An 8 V power source is charging a capacitor. how many volts will be across the capacitor at the second time constant? | 7 volts |
| A capacitor's rate of charge is considered: | exponential |
| A source voltage across a capacitor will: | lag the current by 90 degrees |
| Power stored from the source and than returned to the source is called: | reactive pwer |
| If an open capacitor is checked with an ohmmeter, the needle will: | show infinity |
| What is wrong with a leaky capacitor? | The dielectric resistance has decreased. |
| In a circuit, an output capacitor and a resistor are connected in series with an ac signal. What filter action will be the result? | low-pass |
| In an ac circuit, a capacitor and an out-put resistor are connected in series with an ac signal. What filter action will be the result? | hight-pass |
| A capacitor and an output capacitor resistor from a series circuit with a SQUATE wave applied. The circuit is: | a differentiator |
| A resistor and output capacitor from a series circuit with a square wave applied. The circuit is: * | an integrator * |
| The reactance of a capacitor in a DC circuit is: | Infinity |
| What is the value of a capacitor connected to a 500 kHz AC source that has 1 k ohms of resistance? C=1/2^fXc | 318pF |
| What is the value of theta for an AC circuit that consists of a 10 ohm series resistor and a capacitor with a reactance of 15 ohms? TAN(O)=opp/ADJ= -5ohm/10ohm | 0=TAN-1(-15/10)=-56.3deg. |
| Power that is stored from a source and than return to the source is called: | reactive power |
| **Power that is measured in voltage-amperes is called: | apparent power |
| If the reactive power of a circuit is 50 mw, while the apparent power is 64 mw, than what is the true power of the circuit? Pt=sqr/(Pa)sq-(Pr)sq | sqr(.064)sq-(.050)sq= 40mw |
| What is the power factor if the apparent power of a circuit is 5 w, while the true power is 4 W? P.F.=Cos(0)= Pt/Pa= 4W/5W= | 0.8 |
| What is the capacitive reactance? 1v, 15kHz, 3.3uf Xc=1/2^fc 1/ 2^(150000Hz)(3.3)(10)-6F=?1/x | Xc = 3.2 ohms |
| **If the dielectric strength of a capacitor is decreased, than its capacitance will: | decrease |
| ?**In a 29 V Ac series RC circuit, if 20 volts is read across the resistor and 40 volts is measured across the capacitor, the applied voltage is: | ?45 volts 50 volts 55 volts 60 volts |
| ?**What is the impedance of a 60 Hz, 2 V AC circuit that consists of a 22uf capacitor, and a 100 ohm resistor connected in parallel? | *180 ohms 62.7 ohms 44.6 ohms 128 ohms |
| **A capacitor rate of charge is consider: | exponential |
| **Power that is measured in volt-amperes is call: | apparent power |
| ?**What is the total current in a Parallel circuit consisting of a 1.27 uf capacitor, and a 50 ohm resistor, with a 2.5 kHz, 10 V AC supply? | 400 mA |
| ?**Power that is measured in volt-amperes is called: | apparent power |
| **What is the total current in a parallel circuit consisting of a 1.27 uf capacitor, and resistor, and a 50 ohm resistor, with a 2.5 Khz, 10 V AC supply? | 400MA |
| When a good capacitor is ohmeter checked with a DDM, the bar graph display will: | Show infinity |
| ?**If a 500 UF capacitor has stored 2 coulombs of charge, than what is the voltage across the capacitor? | ? 250 uv 1 mv 1 kv 4 kv |
| ? What is the time to charge the capacitor? series: 12 v, R1 11ohm, C1 ? | 12 ms 10 ms 7 ms ? 5 ms |
| ?**What is the capacitive reactance,of a 4.5 uf capacitor connected to a 1 khz ac source? | 4.7 ohms 34 ohms 29.5 ohms ? 213 ohms |
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