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 : Moving tube electrodes apart to decrease interelectrode capacitance causes an increase in the effect of what property?
Last Answer : Transit time
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 : When the reverse bias on a varactor is increased, what happens to the effective capacitance?
Last Answer : Capacitance decreases.
Description : What happens to inductive reactance as frequency increases?
Last Answer : It increases.
Description : What happens to capacitive reactance as frequency increases?
Last Answer : It decreases.
Description : What happens to the value of XL as frequency increases?
Last Answer : XL increases.
Description : What is the impedance of a crystal at its resonant frequency when it is used in the series mode?
Last Answer : Minimum.
Description : What is the impedance of a crystal at its resonant frequency when it is used in the parallel mode?
Last Answer : Maximum
Description : In swept-frequency testing the impedance of a transmission line, what electrical characteristic is actually being measured?
Last Answer : Swr on the transmission line.
Description : In the illustrated circuit, one advantage of the capacitor coupling over direct coupling is ____________. EL-0048 A. as the frequency decreased the capacitive reactance (Xc) increases B. the amplifier becomes ... of the signal while it isolates the biasing of each stage. D. good frequency response.
Last Answer : Answer: C
Description : The formula for computing impedance in a series circuit containing resistance, capacitance, and inductance is _____________. [ NOTE: the symbol * stands for 'multiplied by' ] A. Z = RT + XL + XC B. Z = R + XL - XC C. Z * Z = R * R + (XL - XC) * (XL - XC) D. Z = R * R + (XL * XC) - (XL * XC)
Description : What is the velocity factor of coaxial cable with a characteristic impedance of 50Ω and capacitance of 30pF/ft and inductance of 75 nH/ft? A. 0.58 B.0.68 C. 0.98 D. 0.81
Last Answer : B.0.68
Description : Referred to the dielectric constant of a transmission line material. A. Inductance and capacitance B. Velocity factor C. Characteristic impedance D. Propagation velocity
Last Answer : B. Velocity factor
Description : In AC Circuit Theory, the term that replaces the resistance is: w) inductance x) capacitance y) impedance z) reactance
Last Answer : ANSWER: Y -- IMPEDANCE
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 : What effect does an increase in capacitance have on a capacitor’s opposition to current flow?
Last Answer : Opposition to current flow 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 : 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 : 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 : Examine the three capacitors shown below. What is the capacitance of each?
Last Answer : a. 26µF or 260,00pF b. 630pF c. 9600pF
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 : What happens to the permeability of an iron core as the current increases from the operating point to a large value?
Last Answer : Permeability decreases
Description : If the permeability of the core of a coil increases, what happens to (a) inductance and (b) true power in the circuit?
Last Answer : (a) Inductance increases; (b) true power decreases.
Description : If inductance increases in a series LR circuit, what happens to true power?
Description : What happens to the speed of electromagnetic energy traveling through air as the altitude increases?
Last Answer : Speed increases
Description : According to Ohm’s law, what happens to circuit current if circuit resistance (a) increases, (b) decreases?
Last Answer : (a) Current decreases (b) Current increases
Description : According to Ohm’s law, what happens to circuit current if the applied voltage (a) increases, (b) decreases?
Last Answer : (a) Current increases (b) Current decreases
Description : The fiber's normalized frequency (V) determines how many modes a fiber can support. As the value of V increases, will the number of modes supported by the fiber increase or decrease?
Last Answer : Increase.
Description : What device is used to produce a gradual change in impedance at the end of a waveguide?
Last Answer : Horn.
Description : What is the result of an impedance mismatch in a waveguide?
Last Answer : Standing waves that cause power losses, a reduction in power handling capability, and an increase in frequency and sensitivity.
Description : What components form the input-signal-developing impedance for the amplifier?
Last Answer : C2 and the secondary of T1.
Description : If the output impedance of an amplifier circuit is decreased, what is the effect on the gain?
Last Answer : The gain decreases.
Description : If the input-signal-developing impedance of an amplifier is increased, what is the effect on the gain?
Last Answer : The gain increases.
Description : In a parallel-resonant circuit, what is the relationship between impedance and current?
Last Answer : Maximum impedance, minimum current.
Description : In a series-RLC circuit, what is the condition of the circuit if there is high impedance, low current, and low reactance voltages
Last Answer : Nonresonant (circuit is either above or below resonance)
Description : . In an "ideal" resonant circuit, what is the relationship between impedance and current?
Last Answer : Impedance low Current high.
Description : When compared to the JFET, what is the input impedance of the MOSFET?
Last Answer : The MOSFET has a higher input impedance.
Description : If the impedance of the choke is increased, will the ripple amplitude increase or decrease?
Last Answer : Decrease.
Description : The actions of the tr and atr circuits depend on the impedance characteristics of what length of transmission line?
Last Answer : Quarter-wavelength section
Description : What is the result of an impedance mismatch between a receiver or transmitter and its transmission line or antenna?
Last Answer : High vswr, which equates to poor reception or a loss of power output.
Description : What do impedance-angle meters and vector bridges have in common?
Last Answer : Both measure phase angle and magnitude in determining impedance.
Description : What is the range of the characteristic impedance of lines used in actual practice?
Last Answer : Between 50 and 600 ohms.
Description : What symbol is used to designate the characteristic impedance of a line, and what two variables does it compare?
Last Answer : Z0 and it is the ratio of E to I at every point along the line.
Description : Which preamplifier design (high-impedance or transimpedance) provides improvements in bandwidth and greater dynamic range with some degradation in sensitivity from an increase in noise?
Last Answer : Transimpedance.
Description : What is the difference between calculating impedance in a series ac circuit and in a parallel ac circuit?
Last Answer : In a series circuit impedance is calculated from the values of resistance and reactance. In a parallel circuit, the values of resistive current and reactive current must be used to calculate total impedance.