Q.1    An astable 555 timer has the following number of stable states?
A)    0
B)    1
C)    2
D)    3
Ans : A

Q.2    What is the difference between an astable multivibrator and a monostable multivibrator?
A)    The astable is free running.
B)    The astable needs to be clocked.
C)    The monostable is free running.
D)    None of these
Ans : A

Q.3    The output of the astable circuit _____?
A)    constantly switches between two states
B)    is LOW until a trigger is received
C)    is HIGH until a trigger is received
D)    floats until triggered
Ans : A

Q.4     Is the circuit in Figure an astable multivibrator or a monostable multivibrator?