Description : Examine the three capacitors shown below. What is the capacitance of each?
Last Answer : a. 26µF or 260,00pF b. 630pF c. 9600pF
Description : Alternating current circuits develop resistance, inductance, and capacitance. The capacitance of individual capacitors is expressed in _____________. A. ohms B. mhos C. henrys D. farads
Last Answer : Answer: D
Description : Moving tube electrodes apart to decrease interelectrode capacitance causes an increase in the effect of what property?
Last Answer : Transit time
Description : In the schematic of the electrical circuit shown in the illustration, what is the value of the total capacitance, when compared to the value of equal individual capacitors? EL-0038 A. Equal B. Half C. Double D. Squared
Last Answer : Answer: C
Description : Combined capacitance is equal to the A. sum of all capacitance of capacitors B. product of all the capacitance C. difference between the capacitors D. average capacitance of capacitors
Last Answer : sum of all capacitance of capacitors
Description : The effective capacitance of four, 5-microfarad capacitors connected in series is: w) 0.20 microfarad x) 0.5 microfarad y) 1.0 microfarad z) 1.25 microfarad
Last Answer : ANSWER: Z -- 1.25 MICROFARAD
Description : Three capacitors with different capacitances are connected in series. Which of the following statements is TRUE? w) All three of the capacitors have the same potential difference between their plates. x ... y) The capacitance of the system depends on the voltage applied across the three capacitors.
Last Answer : ANSWER: X -- THE MAGNITUDE OF THE CHARGE IS THE SAME ON ALL OF THE CAPACITOR PLATES
Description : Three capacitors 15µf, 18µf and 12µf are connected in a circuit. Find equivalent capacitance when they are connected in – 1) Series 2) Parallel
Last Answer : Ans: Value of equivalent capacitance: Given: C1= 15μF, C2=18 µF, C3= 12µF i)For Series combination of capacitors: 1/Cs = (1/C1)+( 1/C2) +(1/C3) = (1/15)+( 1/18)+( 1/12) 1/Cs = 0.0666+0.0555+0. ... Cs = 4.868 µF ii) For parallel combination of capacitors: Cp = C1 + C2 + C3 = 15 +18+ 12 = 45 µF
Description : How will the total capacitance change, when two capacitors are connected in parallel?
Last Answer : The capacitance will increase if connected in parallel because it will be like you have increase surface area of a plate by connecting it to another.
Description : Modern capacitors which have high capacitance in small size use a dielectric of (A) paper (B) rubber (C) ceramic (D) Mylar
Last Answer : Modern capacitors which have high capacitance in small size use a dielectric of ceramic
Description : Equivalent capacitance ‘C’ of a system of capacitors C1,C2,C3 connected in parallel is
Last Answer : Equivalent capacitance ‘C’ of a system of capacitors C1,C2,C3 connected in parallel is C = C1+C2+C3
Description : what will be the capacitance if three capacitors connected in parallel each having value of 0.5 micro Farad ?
Last Answer : the total capacitace when connected in parallel Tc=total capacitor c1=c2=c3=0.5uf Tc=c1+c2+c3 Tc=1.5uf
Description : What type of current is eliminated by synchro capacitors?
Last Answer : Magnetizing current.
Description : Trade-offs between competing effects are necessary for high speed response. Which competing effect (fast transit time, low capacitance, or high quantum efficiency) requires a thin active area?
Last Answer : Fast transit time.
Description : What is the opposition to current flow in an AC circuit caused by an inductor called?
Last Answer : Need answer
Description : Which of the following statements concerning AC circuits is correct? A. The power factor of a resistive circuit is always zero. B. True power in an inductive circuit always equals apparent power. ... . D. Total opposition to the flow of alternating current depends upon the amount of reactive power.
Description : What term is given to total opposition to ac in a circuit?
Last Answer : Impedance
Description : What is the term for the opposition that a capacitor presents to ac?
Last Answer : Capacitive reactance.
Description : What is the formula used to compute the value of this opposition?
Last Answer : XL = 2πfL.
Description : What is the term for the opposition an inductor presents to ac?
Last Answer : Inductive reactance.
Description : Before working on electrical equipment containing capacitors, what should you do to the capacitors?
Last Answer : Discharge them by shorting them to ground.
Description : What tool is used to de-energize capacitors in a circuit that has been disconnected from its power source?
Last Answer : Shorting probe.
Description : Why are synchro capacitors placed physically close to differentials transmitters and CTs?
Last Answer : To keep the connections as short as possible in order to maintain system.
Description : How are synchro capacitors connected in a circuit?
Last Answer : They are delta-connected across the stator windings.
Description : What type of synchros usually require the use of synchro capacitors?
Last Answer : TDXs, CDXs, and Cts.
Description : In a full-wave voltage doubler, are the capacitors connected in series or in parallel with the output load?
Last Answer : In parallel.
Description : Why is the use of large value capacitors in filter circuits discouraged?
Last Answer : Expense
Description : Which oscillator uses tapped capacitors for feedback?
Last Answer : Colpitts.
Description : Charged capacitors can kill. True or false?
Last Answer : True.
Description : During avalanche effect breakdown, what limits current flow through the diode?
Last Answer : an external current-limiting resistor
Description : What is the effect of current flow through the coil in a d’Arsonval meter movement?
Last Answer : A magnetic field is generated around the coil and the attraction of this field with the permanent magnet causes the coil to move
Description : Capacitance in an AC circuit will _____________. A. stop current flow once the capacitor is fully charged B. allow current flow in only one direction C. oppose any change in circuit voltage D. rectify the current
Description : When a megohmmeter is used to test the insulation of a large motor, the initial dip of the pointer toward 'zero' is caused by ____________. A. good insulation B. the capacitance of the ... of the current along the surface of dirty insulation D. the dielectric-absorption effect of the insulation
Last Answer : Answer: B
Description : When using a megohmmeter to test the dielectric strength of wire insulation, a continuous series of slight downscale kicks by the pointer is result of ____________. A. good insulation B. the ... dirty insulation C. the capacitance of the windings D. the dielectric-absorption effect of the insulation
Description : When a megohmmeter is used to test the dielectric strength of wire insulation, the initial dip of the pointer toward 'zero' is caused by _____________. A. good insulation B. the leakage of ... of dirty insulation C. the capacitance of the circuit D. the dielectric absorption effect of the insulation
Description : What type of feedback is usually caused by the base-to collector interelectrode capacitance?
Last Answer : Degenerative or negative
Description : What type of feedback is usually caused by interelectrode capacitance?
Last Answer : Negative (degenerative) feedback
Description : When an unknown capacitance is tested with a bridge, what is the value of Cx if R1 equals 70 ohms, R2 equals 150 ohms, and Cs equals 550 microfarads?
Last Answer : 256 microfarads.
Description : When the reverse bias on a varactor is increased, what happens to the effective capacitance?
Last Answer : Capacitance decreases.
Description : A transmission line is said to have distributed constants of inductance, capacitance, and resistance along the line. What units of measurement are used to express these constants?
Last Answer : Inductance is expressed in micro henrys per unit length, capacitance is expressed in picofarads per unit length, and resistance is expressed in ohms per unit length.
Description : . What are two of the three physical factors that determine the values of capacitance and inductance of a transmission line?
Last Answer : (1) Type of line used, (2) dielectric in the line, and (3) length of line.
Description : Should the capacitance of the photodetector be kept small or large to prevent the RC time constant from limiting the response time?
Last Answer : Small
Description : What happens to the impedance of interelectrode capacitance as frequency increases?
Last Answer : Impedance decreases.
Description : How does the addition of a screen grid in a tetrode reduce interelectrode capacitance?
Last Answer : The interelectrode capacitance (cpg) is divided between two series capacitances; thus, cpg is greatly reduced.
Description : What happens to the value of XC as capacitance increases
Last Answer : XC decreases.
Description : State three factors that affect the capacitance of a capacitor.
Last Answer : a. The area of the plates. b. The distance between the plates. c. The dielectric constant of the material between the plates.
Description : Copper is often used as an electrical conductor because it _______________. A. has high resistance at low temperatures B. has a highly polished surface C. is able to pass current with little opposition D. holds insulation together well
Description : The use of four diodes, in a full-wave bridge rectifier circuit, will __________. A. provide unidirectional current to the load B. allow a very high leakage current from the load C. convert direct current to alternating current D. offer high opposition to current in two directions
Last Answer : Answer: A