Multivibrators and 555 Timer Questions and Answers
Multivibrators and 555 Timer questions with answers help electronics aspirants strengthen their understanding of pulse generation and timing circuits. The 555 timer IC is widely used in monostable, astable, and bistable multivibrator configurations, making it a frequent topic in exams like DRDO, ISRO, and GATE. Mastering these circuits enhances conceptual clarity in waveform generation, duty cycle control, and timing applications. This section provides well-explained aptitude questions and answers that simulate actual electronics exams, helping students test their theoretical knowledge through practical problem-solving. Whether preparing for technical interviews or competitive electronics tests, this topic gives you an edge through step-by-step solutions and real-world applications of timing circuits.
Multivibrators and 555 Timer
41. A bidirectional 4-bit shift register is storing the nibble 1101. Its input is HIGH. The nibble 1011 is waiting to be entered on the serial data-input line. After three clock pulses, the shift register is storing ________.
- 1101
- 0111
- 0001
- 1110
42. How can parallel data be taken out of a shift register simultaneously?
- Use the Q output of the first FF.
- Use the Q output of the last FF.
- Tie all of the Q outputs together.
- Use the Q output of each FF.
43. What is meant by parallel load of a shift register?
- All FFs are preset with data.
- Each FF is loaded with data, one at a time.
44. What does the output enable do on the 74395A chip?
- It determines when data can be loaded.
- It forces all outputs to go HIGH.
- It forces all outputs to go LOW.
- It activates the three-state buffer.
45. To operate correctly, starting a ring shift counter requires:
- clearing all the flip-flops
- presetting one flip-flop and clearing all others
- clearing one flip-flop and presetting all others
- presetting all the flip-flops