30 Figure 4B.Bridge rectifier. IN ANSWERING QUESTIONS 4-18 AND 4-19, REFER TO FIGURE 4-B. 4-18. When the voltage across the secondary of the transformer has the polarity shown, which of the diodes will conduct? 1. D1 and D3 2. D2 and D4 3. D1 and D2 4. D3 and D4 4-19. When the polarity reverses, which of the diodes will conduct? 1. D3 and D1 2. D4 and D2 3. D2 and D1 4. D4 and D3 4-20. In filter circuits, inductors are used as what type of impedance(s)? 1. Shunt impedance to oppose changes in current 2. Shunt impedances to oppose changes in voltage 3. Series impedances to oppose changes in current 4. Series impedances to oppose changes in voltage 4-21. To retain its charge, the capacitor in a simple capacitor filter must have a long charge time constant and a short discharge time constant. 1. True 2. False 4-22. If you increase the value of a capacitor, the X_{C} will increase. 1. True 2. False 4-23. To obtain a steady dc output in a simple capacitor circuit, the capacitor must charge almost instantaneously to the value of the applied voltage. 1. True 2. False 4-24. Which of the following factors, if any, determines the rate of discharge of the capacitor in a filter circuit? 1. The value of the load resistance2. The amount of voltage 3. The type of capacitor 4. None of the above 4-25. A half-wave rectifier has an output frequency of 60 hertz, a filter capacitor value of 40 microfarads, and a load resistance of 10 kilohms. What is the value of X_{C}? 1. 133.3 ohms 2. 26.5 ohms 3. 66.3 ohms 4. 40.0 ohms