diff --git a/content/notes/02-combinatorial-logic.md b/content/notes/02-combinatorial-logic.md
index 1d3bb8fd6..7ed2385b8 100644
--- a/content/notes/02-combinatorial-logic.md
+++ b/content/notes/02-combinatorial-logic.md
@@ -62,10 +62,16 @@ Creating boolean equations:
 ![simple transistor diagram|100](https://i.imgur.com/oBuNR9m.png)
 
 - B: Base ⇒ A swtich connecting C to E
-	- c
+	- open (C is disconnected from E) when supplied 0v
+	- closed (C is connected to E) by applying +5V
 - C: Collector
 - E: Emitter
 
+Possible to create NAND gate using just transistors ∴ possible to create all logic gates using only transistors [^3]
+
+# Demultiplexor
+- Mutli way swtich where the address determines which output recieves the input
+- [2 bit address diagram and truth table](https://i.imgur.com/XQteI3j.png)
 
 # Logic Gates
 - NOT
@@ -79,4 +85,5 @@ Creating boolean equations:
 
 
 [^1] : In real circuits propagation delay must be considered, hence the clock cycle on CPUs
-[^2] : The Apollo Guidance Computer used about 5600 NOR gates and no other gate types!
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+[^2] : The Apollo Guidance Computer used about 5600 NOR gates and no other gate types!
+[^3] : They dont actually do it this way (see lab)
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