Procedure

Fig 1: Circuit Diagram for Q meter experiment

1. Set the Shunt Resistance (R_sh) value as small as possible (Say 0.02 Ohm). Set all the parameters (R, L, C) by yourself.
2. Set the voltage value of the oscillator (E=10 V).
3. At f=100 Hz. Check the value of voltage drop across capacitor. (E_C).
4. Change the frequency until EC reach at the maximum value. Then calculate the value Q measured using this formula

$$ Q_(meas)=\frac{\omega_0L}{R+R_(sh)} $$

5. Calculate the true value of unknown coil by using this formula

$$ Q_(true)=\frac{\omega_0L}{R} $$

6. First resonance occurs due to frequency (say f₁). Note down the value of tuning capacitor C. (say C₁). Double the input frequency (f₁) (say f₂=2*f₁). Change the tuning capacitor value until resonance occurs. Note down the value of tuning capacitor C. (say C₂). Discharge capacitance (C_d) would be =(C₁-4*C₂)/3.