What is the difference between an astable multivibrator and a monostable multivibrator?
-
The astable is free running. -
The astable needs to be clocked. -
The monostable is free running. -
none of the above
If Vcc of a 555 timer circuit is set to +10 V what is the level of output voltage from the circuit?
-
VOH = 10 V, VOL = 0 V -
VOH = 10 V, VOL = 0.1 V -
VOH = 8.5 V, VOL = 0 V -
VOH = 8.5 V, VOL = 0.1 V
Is there any limit to the number of times that a 74123 can be retriggered?
-
yes -
no
If the resistor in the Schmitt trigger astable multivibrator is a variable resistor, what part of the output voltage waveform will change when the resistance is changed?
-
the shape of the waveform -
the amplitude of the waveform -
the period of the waveform -
none of the above
Which of the following is NOT a characteristic of a retriggerable monostable multivibrator?
-
It is a dual multivibrator. -
It has an active-HIGH reset, which terminates all timing functions. -
It has no internal timing resistor. -
none of the above
Which of the following is NOT a characteristic of a retriggerable monostable multivibrator?
-
It is a dual multivibrator. -
It has an active-HIGH reset, which terminates all timing functions. -
It has no internal timing resistor. -
none of the above
The pulse width out of a one-shot multivibrator increases when the:
-
supply voltage increases -
timing resistor decreases -
UTP decreases -
timing capacitance increases
The output of the astable circuit ________.
-
constantly switches between two states -
is LOW until a trigger is received -
is HIGH until a trigger is received -
floats until triggered
The pulse width out of a one-shot multivibrator increases when the:
-
supply voltage increases -
timing resistor decreases -
UTP decreases -
timing capacitance increases
The pulse width out of a one-shot multivibrator increases when the:
-
supply voltage increases -
timing resistor decreases -
UTP decreases -
timing capacitance increases
If a diode is connected across resistor RB (positive end up) in the given figure, what is the new duty cycle of the output waveform?
-
56% -
44% -
21.6% -
17.4%
If a diode is connected across resistor RB (positive end up) in the given figure, what is the new duty cycle of the output waveform?
-
56% -
44% -
21.6% -
17.4%
Pulse stretching, time-delay, and pulse generation are all easily accomplished with which type of multivibrator circuit?
-
astable -
monostable -
multistable -
bistable
What is the difference between a retriggerable one shot and a nonretriggerable one shot?
-
The nonretriggerable can only be triggered once. -
The retriggerable can be triggered many times. -
The output pulse can be stretched with a nonretriggerable. -
The output pulse can be stretched with a retriggerable.
What controls the output pulse width of a one shot?
-
the clock frequency -
the width of the clock pulse -
an RL time constant -
an RC time constant
The internal circuitry of the 555 timer consists of ________, an R-S flip-flop, a transistor switch, an output buffer amplifier, and a voltage divider.
-
a comparator -
a voltage amplifier -
two comparators -
a peak detector
Triggering a retriggerable one shot during pulse generation will:
-
time out the original pulse -
extend the pulse to this trigger width -
have no effect -
double the original pulse width
What controls the output pulse width of a one shot?
-
the clock frequency -
the width of the clock pulse -
an RL time constant -
an RC time constant
What is the function of the comparators in the 555 timer circuit?
-
to compare the output voltages to the internal voltage divider -
to compare the input voltages to the internal voltage divider -
to compare the output voltages to the external voltage divider -
to compare the input voltages to the external voltage divider
The bistable multivibrator is an R-C flip-flop.
-
True -
False