This document discusses several electrical components: variable resistors which allow adjusting resistance without physical changes, thermistors which change resistance with temperature and are used for temperature sensing, switches which control current flow by opening and closing circuits, and fuses which break circuits if current exceeds their rating to provide overcurrent protection. Learning objectives cover distinguishing variable resistor types, how thermistors and switches work, and applications of thermistors and fuses.

1. Fundamentals of Electronic
Section 5a :Electrical Components

2. Learning Objectives
1. Distinguish between type of variable resistor
2. Recognize how thermistors work and their
applications
3. Recognize how switches work
4. Recognize how fuses work and their
applications
5. Recognize how capacitors work and their types.

3. Resistors and Current
 The relation between resistance and current
is inversely
 Variable resistors allow us to have resistance
and current without changing the resistor
physically .

4. Parts of variable resistor
Rotating Wiper
Shaft
Resistive Material
Terminals

6. Special Resistor
• Thermistors (Change with temperature )
• Positive temperature coefficient -PTC
• Negative temperature coefficient -NTC
APPLICATION
• Temperature sensing (Car temperature monitoring)
• Current limiting(oppose the flow of current )
• Circuit protection (protect circuit by limit the amount of current )

7. Switch Schematic diagram Image
Toggle switch
Pushbutton switches
Switches
(1 or 0) (ON or OFF)

8. Switches
Open state
• Pushbutton is not pressed
• Open
• Off
• Zero
• No current
• No voltage
Close state
• Pushbutton is pressed
• Close
• On
• One
• Current flow
• Voltage

9. Fuses
Electrical safety device that remove electrical current when the current is
too high
• Fuse rating : The electrical current that will blow or
break the fuse .
• Fuse rating =(power watt/voltage)*1.25