Full Wave Voltage Doubler

The full wave power supply in Fig. 14.8 delivers 34 volts, twice the amount provided by the previous circuit. When the top of the coil is positive, the +17 

As was mentioned on page 75, there is a great deal of room for creativity in electronics. One of the huge number of clever circuits that have already been invented is shown in Fig. 14.9, and many more are being devised every day. In this circuit, called a Cockcroft-Walton multiplier, an ac voltage can be multiplied by four. 

If another two capacitors and two diodes are added to the circuit in the same manner, the total output can be six times the voltage, and one more set would give eight times the voltage, etc. These ideas were used by scientists named Cockcroft and Walton to build million-volt power supplies for nuclear atom smashers, and now they are used in thousand-volt supplies for portable TV sets. 

On pages 110 and 138, capacitors were used as snubbers, to absorb the inductive kick from a quickly tumed-off inductor. Another way to do this is to attach a PN diode, not across the switch as on page 138, but across the coil, as in Fig. 14.10. 

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An improvement to the conventional and cascade doublers shown above is the bridge rectifying doubler. Instead of half wave rectification, a bridge doubler provides full wave rectification. The advantages of full wave rectification include less input impedance and a ripple voltage at twice the input frequency, which improves ripple-filtering capability. The schematic for the bridge doubler is shown in Fig. 10.10. The IsSpice equivalent schematic is shown in Fig. 10.11. 

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