Reference no: EM131367792
1. What would be the time constant in an RC circuit when R = 200 kn and C = 10 f.lF?
A. 20 sec C. 2 sec
B. 5 sec D. 0.5 sec
2. The simplest clamping circuit consists of a
A. diode and capacitor. C. capacitor and resistor.
B. diode and resistor. D. capacitor and inductor.
3. When a pulse is amplified in a linear amplifier, the charge carrier transmit time can cause
A. loss of the d-e reference levels.
B. rise-time distortion.
C. waveform tilt.
D. propagation delay.
4. It requires 5 time divisions for a pulse to go from 10% to 90% of full amplitude. The sweep of the scope is calibrated so that 10 f.lSec are represented by 20 divisions. What is the rise time of the pulse?
A. 0.25 p.sec C. 10 p.sec
B. 2.5 p.sec D. 15 p.sec
5. In a certain LR time constant circuit, it takes 135 msec for the current to reach maximum after the switch is closed. If the inductance is 4 henrys, what is the value of circuit resistance?
A. 670 n
B. 148 n
c. 0.670 n
D. o.l48 n
6. When you increase the width of a pulse, you
A. decrease average value. C. increase overshoot.
B. decrease duty cycle. D. increase RMS value.
7. Which of the following will most likely cause arcing at the switch contacts?
A. A switch that starts current flowing in an LR time constant circuit
B. A switch that opens an LR time constant circuit
C. A switch that starts the capacitor charge in an RC time constant circuit
D. A switeh--that opens an R-b'-time constant circuit fer ihe capacitor to discharge
8. In a certain circuit the output signal is NOT permitted to exceed a certain value even though the input signal tries to drive it beyond that value. What is the circuit?
A. Limiter C. Baseline stabilizer
B. Clipper D. Ringing oscillator
9. How would you describe a differentiator?
A. An RC circuit where the time constant is greater than 1.
B. An RC circuit where the time constant is equal to 1.
C. A circuit that has an output signal proportional to the sum of input pulses.
D. A circuit that has an output signal proportional to the rate of change of the input signal.
10. Of the following devices, which one is most suitable for frequency domain displays?
A. Memory scope C. Spectrum analyzer
B. Oscillograph D. Triggered sweep scope
11. An NPN common emitter transistor, when operated without d-e bias, can be used as a
A. d-e restorer. C. positive peak clipper.
B. negative peak clipper. D. baseline stabilizer.
12. What is the bandwidth of an amplifier that produces a square wave with a rise time of 2 p.sec?
A. 20kHz C. 70kHz
B. 57 kHz D. 175kHz
13. Determine the duty cycle for the pulse shown below.
A. 9%
B. 23%
c. 27%
D. 80%
14. When working with pulse generators, you should be aware that a monostable multi, vibrator is also a(n)
A. collector-coupled multivibrator. C. astable multivibrator.
B. one-shot multivibrator. D. bilateral compressor.
15. How long will it take for the current to reach 36.7% of its initial value in an inductive discharge circuit if R equals 1000 n and L equals 4 henrys?
A. 40 sec C. 0.004 sec
B. 10 sec D. 0.001 sec
16. An oscilloscope grid is calibrated so that one square represents 1-V vertically and 1 msec horizontally. If the height of a square wave pulse display is 6 squares, the width of the pulse is 7 squares, and the cycle of the wave is 16 squares, the average value of the pulse is
A. 1.73 V.
B. 2.63 v.
c. 3.97 v.
D. 4.32 V.