problem 1: With an appropriate standard coil joined to a Q-meter resonance is obtained with a frequency f1 with resonating capacitor set at C1; the indicated Q-factor is Q1. The unknown impedance is joined in series with the standard coil and resonance is re-established by re-setting the resonance capacitor at C2, the corresponding Q-factor being Q2. Find out:
a) The resistive
b) Reactive components of the unknown impedance
When C1 = 208 pF, Q1 = 80, C2 = 184pF and Q2 = 50. And the frequency is 165 kHz.
problem 2: A coil is tuned to resonance at 500 KHz with resonating capacitance of 36 µµF. At 250 kHz the resonance is obtained with a resonating capacitance of 160 µµF. Find out the self-capacitance and inductance of the coil.
problem 3: Tests by using a Q-meter, on a radio-tuning coil to establish the self-capacitance, gave the results shown below:
a) With the radio coil joined normally resonance was obtained at 800 kHz with the tuning capacitor of the Q-meter set at 95 pF.
b) With a standard inductor joined in place of radio coil, resonance was obtained at 2.5 MHz and this condition was not changed when the radio coil was joined in parallel with the standard inductor. Find out the self-capacitance of the radio coil.
problem 4: A circuit comprising of an unknown coil, a resistance and a variable capacitor joined in series is tuned to resonance by using a Q-meter. If the frequency is 450 kHz and the resonating capacitor is set at 250pF, find out the effective inductance and resistance of the unknown coil. The Q-meter points out 105 and the resistance is 0.75?.
problem 5: A coil is tuned to resonance at 1 MHz by a resonating capacitance of 480pF. At 2 MHz the resonance is obtained with a resonating capacitance of 120 pF. Find out:
a) Self-capacitance of the coil
b) True and indicated values of Q when R = 10? for both the measurements.
problem 6: Two sets of measurements were taken out for measuring Q of a coil joined across the test terminals of the Q-meter.
a) F1 = 2Hz, C1 = 450 pF
b) F2 = 4Hz, C2 = 90 pF
Find out the distributed capacitance of coil.