a) 740 ohms ± 5% b) 4700 ohms ± 10% c) 7400 ohms ± 1% d) 47,000 ohms ± 10% Ans: (d)
a) Direct current b) 16 Hz c) 160 Hz d) 16,000 Hz Ans: (d)
a) Direct current b) 160 Hz c) 16Hz d) 16,000 Hz Ans: (a)
a) C has high reactance for high-voltages b) C blocks d.c. voltages c) C has low reactance for low voltages d) None of the above Ans: (b)
a) The d.c. primary current has no magnetic field b) Working component of primary current has the strongest field c) The secondary voltage is maximum for direct current in the primary d) Only variations in the primary current can induce secondary voltage Ans: (d)
a) L-type filter with series C and shunt L is low pass filter b) π-type filter with series C and shunt L is low pass filter c) T−type filter with series C and shunt L is low pass filter d) L-type filter with series C and Shunt C is low pass filter Ans: (d)
a) Zero to 20 Hz b) 20 cps to 20 kHz c) Zero 20 kHz d) 20 cps to 100 kHz Ans: (b)
a) R.F. coupling capacitor in series with the power line b) 50 Hz chokes in series with the power line c) R.F. capacitors in shunt across the power line d) R.F. chokes in shunt across the power line Ans: (c)
a) Parallel resonant L-C circuits in series and in parallel with the load b) Series resonant L-C circuit in series and in parallel with the load c) Series resonant L-C circuits in series with the load and parallel resonant L-C circuit in shunt d) Parallel resonant L-C circuit in series with the load parallel resonant L-C circuit in shunt Ans: (d)
a) Control grid is made more negative b) Plate voltage is made less negative c) Control grid voltage is made less negative d) Screen grid voltage is made less negative Ans: (c)
a) Make the plate current more dependent on plate voltage b) Have the same potential as cathode c) Decrease the grid-plate capacitance as compared with triode d) Eliminate the problem of secondary emission from the plate Ans: (c)
a) True b) False Ans: (a)
a) A.C. input voltage is at its average value of zero b) Anode is made positive by positive alteration of the a.c. input voltage c) Plate is made negative by negative alteration of the a.c. input voltage d) Cathode is made positive Ans: (b)
a) Is applied to cathode b) Is separate from the cathode circuit c) Must be steady voltage d) Is equal to the capacitor bias voltage Ans: (b)
a) High power rating upto 10 kW b) Long warm up time in amplifier circuit c) No hum from heater cathode leakage d) Short service life because of solid construction Ans: (c)