Electrical Communication is a free textbook on the basics of communication technology. See the editorial for more information....


Problems

1. Calculate and plot the resistance characteristics of the crystal of Fig. 2.

2. Plot the various terms of equation 2 and prove graphically that they combine to give the wave of Fig. 10(b).

3. In Fig. 12, the maximum value of the wave Em = 475 volts, and the fundamental frequency is 60 cycles. Capacitors C1 and C2 are each 4 microfarads. Inductor L1 is chosen as 50 per cent greater than the minimum value that will keep cutout from occurring with RL = 5000 ohms. Inductor L2 is the same as L1, The resistances of these coils are 150 ohms each. Calculate the approximate magnitude of the voltage that each component causes to exist across load resistance RL. Justify any assumptions that must be made.

4. Calculate the percentage ripple in Problem 3.

5. Equation 12 gives the low frequency at which the gain of a resistance coupled amplifier is down 3 db, and at which the phase shift is 45°. What will be the frequency for the amplifier of Fig. 19? Does a phase shift of 45° mean that phase distortion is occurring?

6. For the amplifier of Fig. 19 calculate the high frequency at which the amplification is down 3 db. In Fig. 19 triodes were used. How would the amplification compare if two pentodes were used in an appropriate circuit? How would the frequency response compare?

7. Derive equation 18.

8. For the amplifier of Fig. 24, calculate the power output, the plate-circuit efficiency, and the second harmonic distortion.

9. Calculate the angle of flow for both the grid and plate currents for the problem starting on page 296.

10. Repeat the calculations for the class C amplifier starting on page 296, but with a Q point of Ec = -600 volts, and Eb = +2500 volts.

11. A frequency tripler is to be made using a tube that will put out 100 watts of power in class C. What should be the approximate angle of flow, and approximately what power output will be obtained?

12. Derive equations 26 and 27,

13. Derive equation 29.

14. In the oscillator of Fig. 36, the tubes have amplification factors of 13.8 and plate resistances of 12,000 ohms. The grid bias is - 5 volts, and the plate voltage is +100 volts. In operation the oscillations build up until the grid of the first tube is driven slightly positive. For a typical circuit, what will be the maximum alternating output voltage?

15. Present a theory for the operation of a Transistor.



Last Update: 2011-05-18