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Tham khảo tài liệu 'central air conditioner units and refrigeration_9', kỹ thuật - công nghệ, hoá học - dầu khí phục vụ nhu cầu học tập, nghiên cứu và làm việc hiệu quả | Simpo PDF Merge and Split Unregistered Version - http www.simpopdf.com Simpo PDF Merge and Split Unregistered Version - http www.simpopdf.com Figure 92. Full-wave rectifier. pulsating direct current. Such a capacitor is known as a filter capacitor. 14. Inductor L is a filter choke having high reactance at the a.c. frequency and a low value of d.c. resistance. It will oppose any current variations but will allow direct current to flow almost unhindered through the circuit. In order use both alternations of a.c. this circuit must be converted to a full-wave rectifier. 15. Diode used or full-wave rectification. One disadvantage of the half-wave rectifier is that no current is available from the transformer during the negative half-cycle. Therefore some of the voltage produced during the positive half cycle must be used to filter out the voltage variations. This filtering action reduces the average voltage output of the circuit. Since the circuit is conducting only half the time it is not very efficient. Consequently the full-wave rectifier which rectifies both half-cycles was developed for use in the power supply circuits of modern electronic equipment. 16. In a full-wave rectifier circuit two diodes may be used. However in many applications the two diodes are included in one envelope and the tube is referred to as a duo-diode. A typical example of a full-wave rectifier circuit is shown in figure 92. In this circuit a duo-diode is used and the transformer s secondary winding has a center tap. Notice that the center tap current is turned to ground and then through R and inductor L to the cathode filament of V1. The voltage appearing across X and Y is 700 volts a.c. The center tap is at zero potential with 350 volts on each side. 17. Point X of the high-voltage winding is connected to plate P2 and Y is connected to P1. The plates conduct alternately since at any given instant one plate is positive and the other is negative. During one half-cycle P1 will be positive with
