... the name free running oscillator. The time during which the output is either high or low is determined by the two resistors and a capacitor, which are externally connected to the 555 timer. (3) If the frequency of the clock pulse generator is to be 100HZ and I needed to work out the time, I will calculate it by doing this: T = 1?F T = 1/100 T = 0.01secs (4) If the mark to space ratio (or duty cycle) for the astable is to be 9:1 and I had to work out: a) The time T1, when the output voltage is high, I will use the following method. 9+1=10 0.01/10=0.001*9=0.009secs b) The time T2, when the output voltage is low, I will use the following method. 9+1=10 0.01/10=0.001*1=0.001secs (5) Given that C1 is to be 1?f: a) The value of R2 will be TL=0.693*R2*C TL/C=R2=1443? b) The value of R1 will be Th=0.693*(R1+R2)*c Th/0.693C=R1+R2 R1=11544 (6) The preferred value for R1 is 12k? and the preferred value ...

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