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Flip-Flops and Timers - Technical MCQs

Q1:

The equation for the output frequency of a 555 timer operating in the astable mode is: mcq24_1009_1.gif.
What value of C1 will be required if R1 = 1 komega.gif, R2 = 1 komega.gif, and f = 1 kHz?

A 0.33 mu.gifF

B 0.48 mu.gifF

C 480 mu.gifF

D 33 nF

ANS:B - 0.48 mu.gifF

Basic Formula is F = 1.43/(R1+2R2)*C1.
=1=1.43/(1+2*1+C1.

So,
C1 = 1.43/2+1.
= 1.43/3.
= 47666.

ANS 0.48 uF.