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WorksheetsEC - POP QUIZ CHAP 4
Total questions: 10
Worksheet time: 5mins
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
When a capacitor charges:
the voltage across the plates rises exponentially
the circuit current falls exponentially
the capacitor charges to the source voltage in 5×RC seconds
all of the above
The ________ is defined as the time the output is active divided by the total period of the output signal.
On time
Off Time
Duty Cycle
Active ratio
A Monostable mode with 7.5kohm resistor and a 0.02microF capacitor are connected in series to a 5-V source. What is the time of the circuit?
2.85ms
8.25ms
0.825ms
0.285ms
What does the discharge transistor do in the 555 timer circuit?
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
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
Timers are used to activated or de-activate a device after a preset interval of time
TRUE
FALSE
With most timers, the time delay period is fixed and can not be varied.
TRUE
FALSE
For Schmitt-Trigger, the output logic gate state low or high is the inverse of the input state is when the input low (<1/3 Vs) makes output high, +Vs.
TRUE
FALSE
Calculate the frequency when time high is 1.04ms and time low is 0.52ms.
641kHz
6.41Hz
641Hz
0.641Hz
