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--- a/content/notes/02-combinatorial-logic.md
+++ b/content/notes/02-combinatorial-logic.md
@@ -9,10 +9,36 @@ sr-interval: 3
 sr-ease: 250
 ---
 
+- [slides](https://blackboard.otago.ac.nz/bbcswebdav/pid-2954102-dt-content-rid-18888626_1/courses/COSC204_S2DNI_2022/L2%20-%20Combinatorial%20Logic.pdf)
+
+# Combinatorial Logic Circuit
 > [!Definition]
 > Combinatorial Logic Circuit is a circuit whose digital outputs are dependent only on its digital inputs
-> 
-> They can be described using logic expressions and therefore logic gates. We assume the outputs respond immediately^[1]
+They can be described using logic expressions and therefore logic gates. We assume the outputs respond immediately^[1]
+
+They can be defined:
+- Using a truth table
+- Using boolean equations ($Q\ =\ A+\ B$) 
+- Using graphical symbols  
+
+- [1 Bit half adder(https://i.imgur.com/mjCVU4I.png)
+- 1 Bit full adder: (includes carry input) [](https://i.imgur.com/yu6kS83.png)
+ 
 
 
-[^1] : In real circuits propagation delay must be considered, hence the clock c
+# Circuit basics:
+- current flows + to -
+- input to a unit (e.g., LED) is the + end
+
+# Logic Gates
+- NOT
+- AND
+- OR
+- NAND
+- NOR
+- XOR/EOR
+
+
+
+
+[^1] : In real circuits propagation delay must be considered, hence the clock cycle on CPUs