Digital Electronics- Multivibrators and 555 Timer
Digital Electronics- Multivibrators and 555 Timer
31. The 74S124 TTL chip is a voltage-controlled oscillator that will generate a specific frequency at Vout.
- TRUE
- FALSE
32.
A single Schmitt trigger inverter is all that is needed to build a simple astable multivibrator.
A single Schmitt trigger inverter is all that is needed to build a simple astable multivibrator.
- TRUE
- FALSE
34. When the 74123, a retriggerable monostable multivibrator device, ends its timing cycle it must be started all over again.
- TRUE
- FALSE
35. A multivibrator is a circuit that changes between two digital levels on a continuous, free-running basis or on demand.
- TRUE
- FALSE
37. On the fifth clock pulse, a 4-bit Johnson sequence is Q0 = 0, Q1 = 1, Q2 = 1, and Q3 = 1. On the sixth clock pulse, the sequence is ________.
- Q0 = 1, Q1 = 0, Q2 = 0, Q3 = 0
- Q0 = 1, Q1 = 1, Q2 = 1, Q3 = 0
- Q0 = 0, Q1 = 0, Q2 = 1, Q3 = 1
- Q0 = 0, Q1 = 0, Q2 = 0, Q3 = 1
38. The bit sequence 0010 is serially entered (right-most bit first) into a 4-bit parallel out shift register that is initially clear. What are the Q outputs after two clock pulses?
- 0000
- 0010
- 1000
- 1111
39. What is a shift register that will accept a parallel input, or a bidirectional serial load and internal shift features, called?
- tristate
- end around
- universal
- conversion
40. On the third clock pulse, a 4-bit Johnson sequence is Q0 = 1, Q1 = 1, Q2 = 1, and Q3 = 0. On the fourth clock pulse, the sequence is ________.
- Q0 = 1, Q1 = 1, Q2 = 1, Q3 = 1
- Q0 = 1, Q1 = 1, Q2 = 0, Q3 = 0
- Q0 = 1, Q1 = 0, Q2 = 0, Q3 = 0
- Q0 = 0, Q1 = 0, Q2 = 0, Q3 = 0