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(a) Students wants to use tow p-m jusnction diodes to convnet alternating currentinto direct current . Draw the labelled circuit she would use and explain how it works.(b) Give the truth tableand circuit symbolforNAND gate. |
Answer» Solution :(a) Toconvert ALTERNATING currentinto direct currentshe shoulduse fullwave rectifier. Thecircuit diagra and workingof full wave rectifier is as shown :  In this circuitthere are TWO diodes in ODER to rectifyboth the cycleof a . c `I//P`. For this centre taptransformer `(phi^("mer"))` is used . (i) Operationduringpositivehalfcycle : Duringpositive halfcycle `D_(1)`diode is forwardbiasd and hence, wil conduct `Id_(1)` flows through `R_(L)`. In this cyclediode. `D_(2)`is reverse baised and hence, does not conduct. Only `D_(1)`supplies the load current `I_(L) = Id_(I)` .  (ii) Operation during negative half-cycle : Inthe negavtive half cyclepolarity reverse and A becomes- veand `B^(-)` becomes - ve and `B^(-)`becomes`+ ve` hence, the diode `D_(1)`does notconduct but `D_(2)`conducts beingforwards biased currentin the ciruit is as shown DUE to `D_(2)` . 
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