Topic: Analog Circuits
The approximate output Frequency of 555 Oscillator for $R_{A}=R_{B}=2.2~\text{k}\Omega$ and $C=2000~\text{pF}$
- A. 110 kHz
- B. 109.3 kHz
- C. 120.5 kHz
- D. 108.9 kHz
Answer: B. 109.3 kHz
Explanation: The time period of the IC-555 working in astable mode can be given as
$T_{total}=0.693\times(R_{A}+2R_{B})C$
$=0.693\times 3 \times 2.2\times 10^{3}\times 2000\times 10^{-12}$
$=9.147\times 10^{-6} \text{ s}$
Now, $f=\frac{1}{T}$
$f=109.3~\text{kHz}$
Hence option (b).