Question

How to select capacitor value in circuit according to calculation?

Answer 1

I don't know much but this may help you

You choose a capacitor value by using the RC time constant:

\tau = R * C

This constant gives you the time it takes for a voltage in an RC circuit to go from 0% to 63% of its full value.

You can use this time constant to calculate the cutoff frequency in a filter, or just how long a delay will be in a blinking light circuit.

Calculating Capacitor Value For A Circuit

Low-pass filter using a capacitor and a resistor

Let’s say we want to make a low pass filter with a cutoff frequency of 15 kHz. The formula for calculating cutoff frequency is:

f_{c} = \frac{1}{2 \pi RC}

and by switching it around we can calculate for C:

C = \frac{1}{2 \pi R f_{c}}

Now, let’s choose to use a 1k resistor. This gives us:

C = \frac{1}{2 * 3.14 * 1000 \Omega * 15000 Hz} = 0.000000011 = 11 nF

So to get a cutoff frequency of 15 kHz, we need a 1k resistor and a 11 nF capacitor.

hope you understand my solution