Electric Circuits Answers

Find the capacitance of a spherical capacitor filled with a dielectric of dielectric 

constant K.

A circuit is to be designed to keep the voltage across a 50Ω resistor constant when the supply voltage changes. Two resistors of resistances 100 Ω and 50 Ω are connected in series across a 110 V AC source. Determine the voltage across the 50 Ω resistor. If the supply voltage varies between 100 V and 120 V, what is the required range of variations in the 100 Ω resistor required to keep the voltage across the 50 Ω resistor constant? 

1. There are stations having the maximum frequency deviation of 75 kHz, and the maximum audio frequency for the modulation is 15 kHz , find its deviation ratio.
2. Determine the peak frequency deviation for a FM modulator with a deviation sensitivity of 12 kHz/V  and a peak modulating signal of 9V.
3. If the maximum frequency deviation of the carrier is 10 kHz and the maximum modulating frequency is 6.7 kHz, find the modulating index.
4. A PM signal has a maximum allowed deviation of 22 kHz  and an actual deviation of 5 kHz . What is its percent modulation?

A 60 Ω resistor is made by winding platinum wire into a coil at 20°C. If the platinum has resistivity

r=10.4x10-8 Wm at 20°C and the platinum wire has a diameter of 0.10 mm, what length of wire is

needed?