Part of Made in India,Design Innovation

Workshop,2015

A  Fresh  New  Experience  in  

Project-­‐Making  and  Learning

PHYSICS INVESTIGATORY PROJECT ON

NOR GATE USING DIODES

Do  you  know  what  controls  the  working  of  a  washing  machine?  The  concept  of  a  3-­‐input  NOR  gate  will  help  you  understand  this;  it  has  three  inputs  (A,  B  and  C)  and  only  one  output  (Q).  There  are  three  sensors  in  the  washing  machine,  which  provide  inputs  to  the  3-­‐input  logic  gate.  When  all  the  three  inputs  A,  B  and  C  are  low  (0),  the  output  of  the  gate  produces  a  high  output  (1)  due  to  which  the  machine  gets  ON.  

In  case  of  an  erroneous  condiSon,  like  the  lid  is  open  or  water  is  below  the  minimum  level,  the  sensors  provide  high  input  to  the  3-­‐input  logic  gate  due  to  which  the  gate  produces  a  low  output  (0)  and  subsequently,  the  machine  turns  OFF.  

In  this  project,  you  will  make  an  NOR  gate  logic  circuit  using  two  diodes,  two  resistors,  an  LED  and  a  few  connecSng  wires.  Two  connecSng  wires  are  connected  to  the  p-­‐sides  of  the  diodes;  the  n-­‐sides  of  both  the  diodes  are  given  the  same  potenSal.  Each  connecSng  wire  

represents  the  input.  This  input  could  be  either  1  or  0,  where  1  stands  for  Vcc  (posiSve/high  voltage)  and  0  stands  for  ground  (negaSve/low  voltage).

To  provide  the  respecSve  inputs,  the  truth  table  of  OR  gate  is  followed.  

Input  A Input  B Output  Q0 0 10 1 01 0 01 1 0

On  providing  the  inputs,  if  the  LED  glows  this  means  output  Q  =  1  or  high.  If  the  LED  does  not  glow,  the  output  Q  =  0  or  low.  AYer  verifying  the  experimental  outputs  in  four  different  cases  of  the  inputs,  we  do  the  ‘path  of  current’  analysis  and  reason  out  why  the  LED  glows  in  each  case.

Have  a  look  at  our  Project  Kit!

CoolJunk   is   India's   fastest   growing  DIY   (do-­‐it-­‐yourself)   kits   company   focused   on   project-­‐based   learning   in  science,   engineering   and   technology.  Having   20,000   users   in   India,  US,   Singapore,   Middle   East   and   New  Zealand,  the  CoolJunk  kits  are  known   for  quality,  innovaSon   and  high  producSon  value.  CoolJunk  has  been  featured   in   naSonal   and   internaSonal   journals   including   Wallstreet,   Yourstory,   Hindu   Business   Line,  NextBigWhat  and  was  tagged  as  the  coolest  Indian  start-­‐up  in  IAN  Bootcamp-­‐2011.  

For  more  projects  visit  our  website:  CoolJunk  

Tools  and  Components  in  one  box.

Step  by  step  visual  instrucSons

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