DIODE CIRCUITS 



arrangement is called full-wave rectification. It uses rather a lot of diodes 

 and it is possible to do better than this if the generator is of a special kind, 

 that is, it has a 'centre-tap'. In Figure (5.7 the generator seen by the diodes is a 



+ F sin cut 



^ 



T 



R 



>H 



~E sin wt 

 Figure 6.7 



transformer with a centre-tapped secondary winding. Then we have two 

 half-wave circuits working back to back, alternately, and the load current is 

 of the same form as that for the bridge. 



This type of circuit is the most commonly used for power rectification in 

 electronics and the unqualified phrase 'full-wave rectifier' circuit refers to this 

 rather than to the bridge arrangement. It is open to the objection that the 

 transformer insulation has to be able to withstand twice the voltage it would 

 have to in the bridge configuration. The pulsatory outputs of these three 

 rectifier circuits are of very little use as they stand. They are all right for 

 accumulator charging, but mostly are more useful if they are smoothed. We 

 should, however, comment on one extremely important case of unsmoothed 

 bridge rectification. 



1 2 



250VO 

 Common*^ 



Figure 6.8 



The multi-range meter — These versatile instruments are much in evidence 

 in electronic work and it is necessary to issue a word of warning about their 

 use. The voltmeter part of one of these might be arranged like Figure 6.8. 



98 



