1

 
Input Sensors + Voltage Dividers
 

2

 
Voltage Divider Analogy
 

3

 
Output Devices (Lamps etc)
 
4
 
Output Devices (Inductive)
 
5
 
Output Devices (Relays)
 
6
 
The Transistor Switch
 
7
 
The Darlington Pair
 
8
 
Using a Multimeter
 
9
 
Calculate an LED's Resistor