1 .		A monostable 555 timer has the following number of stable states: [Hint]   0   1   2   3
2 .		An astable 555 timer has the following number of stable states: [Hint]   0   1   2   3
3 .		An astable multivibrator requires: [Hint]   balanced time constants   a pair of matched transistors   no input signal   dual J-K flip-flops
4 .		What is another name for a bistable multivibrator? [Hint]   on-off switch   oscillator   flip-flop
5 .		What is the difference between an astable multivibrator and a monostable multivibrator? [Hint]   The astable is free running.   The astable needs to be clocked.   The monostable is free running.   none of the above
6 .		The pulse width out of a one-shot multivibrator increases when the: [Hint]   supply voltage increases   timing resistor decreases   UTP decreases   timing capacitance increases
7 .		When a capacitor charges: [Hint]   the voltage across the plates rises exponentially   the circuit current falls exponentially   the capacitor charges to the source voltage in 5RC seconds   all of the above
8 .		A 22 k resistor and a .02 F capacitor are connected in series to a 5 V source. How long will it take the capacitor to charge to 3.4 volts? [Hint]   .44 ms   .501 ms   .66 ms   .70 ms
9 .		A 0.3 F capacitor has an initial charge of 2.7 volts. If it is discharged through a 10 k resistor for 6.5 ms, how much voltage will be left across the capacitor? [Hint]   0.0 volts   0.309 volt   2.7 volts   2.295 volts
10 .		The _____ is defined as the time the output is active divided by the total period of the output signal. [Hint]   on time   off time   duty cycle   active ratio
11 .		The output of the astable circuit _____. [Hint]   constantly switches between two states   is low until a trigger is received   is high until a trigger is received   floats until triggered
12 .		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? [Hint]   the shape of the waveform   the amplitude of the waveform   the period of the waveform   none of the above
13 .		The monostable multivibrator circuit is not an oscillator because _____. [Hint]   its output switches between two states   it requires a trigger to obtain an output signal   it requires a sine wave input signal   the circuit does not require a dc power supply
14 .		What controls the output pulse width of a one-shot? [Hint]   the clock frequency   the width of the clock pulse   an RL time constant   an RC time constant
15 .		In a typical IC monostable multivibrator circuit, on the falling edge of the trigger input, the output switches high for a period of time determined by the _____. [Hint]   value of the RC timing components   amplitude of the input trigger   frequency of the input trigger   magnitude of the dc supply voltage
16 .		Pulse stretching, time-delay, and pulse generation are all easily accomplished with which type of multivibrator circuit? [Hint]   astable   monostable   multistable   bistable
17 .		Design a circuit using a 74121 to convert a 33 kHz, 30% duty cycle waveform to a 33 kHz, 60% duty cycle waveform. [Hint]   Rint = 2 k, Cext = .012 nF   Rint = 2 k, Cext = .012 F   Rint = 4 k, Cext = .012 nF   Rint = 4 k, Cext = .012 F
18 .		What is the difference between a retriggerable one-shot and a nonretriggerable one-shot? [Hint]   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.
19 .		Which of the following is not a characteristic of a retriggerable monostable multivibrator? [Hint]   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
20 .		A retriggerable one-shot has a pulse of 10 ms; 3 ms after being triggered, another trigger pulse is applied. The resulting output pulse will be ______ ms. [Hint]   3   7   10   13
21 .		Triggering a retriggerable one-shot during pulse generation will: [Hint]   time out the original pulse   extend the pulse to this trigger width   have no effect   double the original pulse width
22 .		Is there any limit to the number of times that a 74123 can be retriggered? [Hint]   Yes   No
23 .		Does the 74123 one-shot have an internal timing resistor? [Hint]   Yes   No
24 .		What is the pulse width of the output of a 74123 if an external 4.7 k resistor and a .022 F capacitor are used? [Hint]   290 ms   29 ms   33.3 s   290 s
25 .		The internal circuitry of the 555 timer consists of _____, an S-R flip-flop, a transistor switch, an output buffer amplifier, and a voltage divider. [Hint]   a comparator   a voltage amplifier   two comparators   a peak detector
26 .		Which mode of operation is being used when a 555 timer chip has two external resistors and an external capacitor? [Hint]   monostable   pulse stretching   Schmitt triggering   astable
27 .		To obtain a 50% duty cycle in an astable 555 timer circuit: [Hint]   tLO = tHI   RA = RB and short RB with a diode during the capacitor charging cycle   capacitor voltage must rise above 1/3 VCC   tLO = tHI, RA = RB, and short RB with a diode during the capacitor charging cycle
28 .		A crystal demonstrates the _____ effect when a mechanical force across the crystal causes a small voltage to be generated.    photoelectric   Colpitts   piezoelectric   flywheel
29 .		What is the function of the comparators in the 555 timer circuit? [Hint]   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
30 .		What does the discharge transistor do in the 555 timer circuit? [Hint]   charge the external capacitor to stop the timing   charge the external capacitor to start the timing over again   discharge the external capacitor to stop the timing   discharge the external capacitor to start the timing over again
31 .		If Vcc of a 555 timer circuit is set to +10 V what is the level of output voltage from the circuit? [Hint]   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
32 .		Determine tHI and tLO for the circuit of Figure 14-1. Figure 14-1 [Hint]   tHI = 7.95 s, tLO = 6.24 s   tHI = 6.24 s, tLO = 7.95 s   tHI = 3.97 s, tLO = 3.21 s   tHI = 3.21 s, tLO = 3.97 s
33 .		What is the duty cycle of the waveform at the output of the circuit in Figure 14-1? [Hint]   78%   56%   50%   44%
34 .		If a diode is connected across resistor RB (positive end up) in Figure 14-1, what is the new duty cycle of the output waveform? [Hint]   56%   44%   21.6%   17.4%
35 .		With most monostable multivibrators, what is the Q output when no input trigger has occurred? [Hint]   LOW   positive +5 V   SET   HIGH
36 .		What is the output pulse width of the waveform at the output of the circuit in Figure 14-2? Figure 14-2 [Hint]   1.65 ms   1.82 ms   4.98 ms   5.46 ms
37 .		Is the circuit of Figure 14-2 an astable multivibrator or a monostable multivibrator? [Hint]   monostable   astable