SPM: Transistor

This topic is a bit tricky, coz in SPM we didnt learn the actual details about transistor working principle and u   need to memorise certain facts. In order to understand a transistor, firstly u must get  to know its structure & terminal. Transistor has 3 terminals, i.e a base, collector & emitter terminal. There are two type of transistor, please make sure u memorize the different between them.

The first type is called N-P-N:

The second type is P-N-P:
Main function of a transistor is to amplify small current.So its a must for u to explain how does a transistor amplify the current.




Transistor as Current Amplifier:
Transistor is a component which relies on the current that flows in its base terminal.
A small changes in base current (Ib) causes bigger change in collector current (Ic).


The analogy is simple, if u attend  morning assembly in school..usually the teacher was talking using a microphone. What actually causes the teacher's voice become louder?? Is it the microphone alone??
Actually..its the amplifier which has a transistor that did the job to amplify the voice.
Please make sure u refer your reference book on its circuit arrangement as well as its experiment.

Transistor as a switch:
This part is important in SPM..u must be able to understand and memorise its circuit arrangement.
To switch ON the transistor, we need to have:

• a higher resistance in the base-emitter circuit 
• this causes a bigger voltage dropped across the resistor in base-emitter circuit
• In the end there's enough current flowing thru the base terminal to switch ON the transistor

i'll discuss detail abt this soon.....to be continued