Which one of the following resistancecapacitance combination

Which one of the following resistance-capacitance combinations has the longest time constant? R = 0.089 M Ohm; C = 0.09 mu F R = 75 k Ohm; C = 0.3 mu F R = 82 k Ohm; C = 27,000 pF R = 88,000 Ohm; C = 0.15 mu F Which one of the following statements is characteristic of the output pulse of a 555 monostable multivibrator? (Assume a positive trigger pulse.) The output pulse ends when the trigger pulse ends. The output pulse ends when the trigger pulse starts. The output pulse starts when the trigger pulse ends. The output pulse starts when the trigger pulse starts. Which one of the following conditions must you avoid when you use a logic pulser to troubleshoot a sine-wave-operated digital clock? Two logic 0 levels at the same point in the circuit Two logic 1 levels at the same point in the circuit Two logic signals in phase at the same point in the circuit Two logic signals out of phase at the same point in the circuit To obtain the greatest possible accuracy in a timing device, you should use a digital timer operated from a crystal-controlled oscillator. 3905 IC operated through an electronic inductor. timer with a unijunction transistor in its circuit. 555 IC operated through an electronic capacitor.

Solution

Ans)

1. Ans----- B

Time constant t=RC

For option A t=7.12 ms

For option B t=22.5 ms

For option C t=2.214 ms

For option D t=13.2 ms

So answer is B it will take longest time t=22.5 ms

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