problem 1: describe the given methods of measuring efficient resistance of a coil by using resonance method:
a) Variation of capacitance.
b) Variation of frequency.
problem 2: describe the circuit and working of the Q-meter. describe its applications.
problem 3: describe the measurement of the given by using Q-meter:
c) Effective resistance.
e) Band width.
problem 4: A capacitance of 250 pF produces resonance with a coil at a frequency of (2/π) ×106 Hz, whereas at the second harmonic of this frequency resonance is generated by a capacitance of 50 pF. Compute:
a) The self-capacitance
b) The inductance of the coil.
Neglect the effect of voltmeter capacitance and as well other stray capacitances.
problem 5: A coil of inductance L is tuned by a capacitance C to resonate at 1 MHz. A standard capacitor of 230 pF is tuned to resonate with similar coil at 2 MHz. If the resonance is indicated by a VTVM of capacitance 8 pF in parallel with the circuit, compute the values of L and C.
problem 6: A constant rms voltage of frequency 3 MHz is applied to a coil of inductance L and resistance R, a calibrated variable capacitor C and a thermo junction all in series. The un-calibrated ammeter is found to show similar scale reading I for the two values of C-namely 37 and 45 pF, one being below and the other above the capacitance C0 required to produce maximum current.
The capacitor is now adjusted to a value C0, and an added series resistance of 75Ω is found to decrease the current to prior value of I. Find out the values of L and R.
problem 7: Compute the Q-factor and effective resistance of a circuit tuned to a frequency of 1.5 MHz and containing an effective resistance of 150 pF. In this circuit the current drops to 70.7% of its resonant value when the frequency of an emf of constant magnitude injected in series with the circuit deviates from the resonant frequency by 5 KHz.
problem 8: The vacuum tube volt meter (VTVM) has been designed for the 1.0 dc output. The input impedance is specified as 1MΩ. Describe how you can incorporate 10 V and 100V multi-range facilities in the instrument.