Transistor Switching

Purpose: To understand the applications of a transistor and analysis of a transistor circuit.

Introduction:
   We will use

• Voltage source
• Breadboard and wire
• DMM
• 2N3904 Transistor
• Pot
• Resistors

Resistors (Ohms):
R1 = 180
R2 = 10k
R3 = 680

Demonstration: We set up the following circuit and when a finger was used to connect the circuit,  the LED would light. This displayed how the transistor can amplify current.

Experiment: To understand how a transistor works we set up the following circuit. 

 R1 and R3 changed to 39 Ohm resistors.

The resistance above and below the transistor is the same until the potentiometer is added to change the voltage  of the base.

We will measure the Amps through the base at A1 and the amps moving through the emitter at A2

Data:

Beginning with the potentiometer halfway we measured the following values.

Conclusion:

     The beta gain of the transistor is 136.02 (if you only use the first 4 points before saturation). It saturates around 0.2 to 0.4 amps.