
//INTEGRAS/ELS/PAGINATION/ELSEVIER UK/PLC/3B2/FINALS-7-6-04/0750656794-CH007.3D – 74 – [71–90/20] 19.6.2004
9:08PM
Hence, it can now be seen that
Red ¼
A.
Amber ¼ B.
Green ¼ A:
B.
The above can also be proved theoretically, using either Boolean Algebra or by using
Karnaugh Mapping techniques.
Principle of ope ration
1. Line 0
When there is no input on X0, i.e. A ¼ 0, then the Red output Y0, will be ON.
Conversely, when A ¼ 1, then the Red output will be OFF.
2. Line 2
The B input X1 is directly connected to the Amber output Y1, hence producing the
truth table below:
B input (X1) Amber output (Y1)
0 OFF
1ON
3. To turn the Green output Y2 ON, then input A should ...