Figure 5.1, Four Most Common Rectifier-Filter Circuits. Common to all four of these circuits is the absents of any schematic connection to the utility power grid. It is assumed that the reader is sufficiently familiar with how transformer primary windings are connected to the A C line that no drawings of the connections are necessary. The transformers are drawn showing their primaries and secondaries but the descriptions below will begin with the secondary.

Part A. Full wave center tapped rectifier with filter capacitor. The transformer secondary has a center tap. The top of the winding goes to the anode of a diode, D1. The bottom goes to the anode of another diode, D2. The center tap connects to common and to the negative output terminal. The cathodes of D1 and D2 are connected together and they connect to the positive side of a filter capacitor. The negative of the capacitor goes to common. The junction point of D1, D2, and the capacitor connects to the positive output terminal of the power supply. End part A.

Part B. Full wave bridge rectifier and filter capacitor. The transformer secondary does not require a center tap. The bridge is made up of four diodes. The top of the transformer secondary goes to the cathode of D1 and the anode of D2. The bottom of the secondary goes to the cathode of D3 and the anode of D4. The anodes of D1 and D3 are tied together and go to common and also to the negative output terminal. The cathodes of D2 and D4 connect to the positive end of a capacitor. The negative end goes to common. The junction of the cathodes of D2 and D4 and the capacitor connect to the positive output terminal of the power supply. End part B.

Part C. A bridge rectifier and a center tapped secondary combine for a dual voltage power supply. The top of the transformer secondary goes to the cathode of D1 and the anode of D2. The bottom of the secondary goes to the cathode of D3 and the anode of D4. The center tap goes to common and center output terminal of the power supply. The anodes of D1 and D3 are tied together and go to the negative terminal of a capacitor. The positive terminal connects to common. The junction of the anodes of D1 and D3 and the capacitor go to the negative, lower, output terminal. The cathodes of D2 and D4 connect to the positive end of a capacitor. The negative end goes to common. The junction of the cathodes of D2 and D4 and the capacitor connect to the positive, upper, output terminal of the power supply. The lower terminal delivers a negative voltage with respect to the center terminal while the upper terminal delivers a positive voltage of the same magnitude with respect to the center terminal.

If we were to declare the bottom output terminal of the three as common the center terminal would deliver a positive voltage and the upper one twice that voltage.

On the other hand if we were to declare the upper output terminal as common the center terminal would deliver a negative voltage. The lower terminal would deliver a negative voltage with twice the magnitude. End part C.

Part D, Full wave voltage doubler. The transformer secondary has no center tap. The upper end of the secondary connects to the anode of D1 and the cathode of D2. The cathode of D1 connects to the positive end of a capacitor, C1. The negative end connects to the positive end of another identical capacitor, C2. The negative end of C2 connects to the anode of D2. The bottom end of the secondary connects to the junction of C1 and C2. The positive end of C1 is the positive output terminal and the negative end of C2 is the negative output terminal of the supply.

If you examine this circuit carefully you will see that it is nothing more than two half wave rectifiers operating from the same transformer winding with their outputs connected in series. End verbal description.
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