Figure 1 show the circuit diagram of RC phase shift oscillator.

The frequency of oscillation $f_O$ is given by,

$$f_o = \frac{1}{2π\sqrt{6}RC} = \frac{0.065}{RC}……….(1)$$

Let C=0.01uF so equation (1) becomes,

$f_O$ = 5KHz……Given

$$R = \frac{0.065}{5 X 10^3 X 0.001 X 10^-6}$$

$$R = 1.3KΩ$$

To prevent the loading of the amplifier because of RC networks, it is necessary that $R_1$ ≥ 10R.

Therefore $R_1$ = 10(1.3KΩ) = 13KΩ

$$|\frac{R_F}{R_1}| = 29$$

Or $R_F$ = 29$R_F$

$$R_F = 29(13kΩ)$$

$$R_F = 377kΩ$$

Use $R_F$ = 390KΩ potentiometer.

Figure 2 shows designed circuit diagram.

Designed Circuit Diagram: