Tansister Switching

In this lab, we examine the properties of a Transistor as a circuit element. We particularly examine an NPN 2N3904 type of transistor due to how common of a part it is.

 

The Transistor essentially acts as a resistor due to its internal chemistry.

 

 

The Following Diagram shows the lab set up of our circuit.

 

 

A2 is a Green LED which we use as an indicator (Power) for the amount of current the transistor lets through.

This video shows my fingers replacing the R2 resister and acts as a switch:

 

 

 



 



After putting on a small light show, we no reintroduce that R2 where my fingers where and started collecting of current flowing through A1 and the Green LED. 

 

R1 = 39.5 Ohm R2 and R4 = 10kOhms  R2 = 39Oms P1 is a Linear Potentiometer

 

 

Using MATLab

MatLab is an engineering program used to solve complex systems. In this particular lab, we used the Matrix function of MatLab to solve a system of equations to find the 2 mesh currents in the circuit:

Once I chose the mesh current directions, I solved a simple system of equation which I then wrote into a matrix. Using the MAGIC of MatLab, I plugged the matrix into the program to solve for the mesh currents needed to find the voltage drop through the 10Ohm resister (parallel to the two voltage supplies).

Voltage Dividers

Introduction to Biasing

Intro To DC Circuits

Lab 1: Using a Multimeter

 

Objective: The objective of this lab is to familiarize ones self with the tools of a circuit analysis laboratory, namely the use of a Digital Multimeter.

 

 

Procedures

1. Resistance Test
2. Voltage Test on DC Power Supply
3. Measuring Voltage Across an LED

Resistance Test: Measure resistance for various resistors, (note colour bands).

Resistor Colours        Value from Colours     Measured Values 

                   Brn, Grn, Brn, Gld        150 Ohms  %5 tol         149.0 Ohms
                   Orng, Blk, Blk, Gld        30 Ohms   %5 tol         30.0 Ohms
                   Orng, Blk, Blk, Gld        30 Ohms   %5 tol         30.2 Ohms
                   Ylw, Prpl, Ylw, Gld       470kOhms %5 tol         .475MOhms

Voltage Test: Measure the Voltage on 9V DC Power Supply/Measure Voltage Drop across 150Ohm Resister.

Value: 9.03V

Voltage Drop across 150Ohm Resister

Measuring Voltage Across LED: Construct circuit from figure in Lab Manual (see picture below), and measure the voltage across Green LED in series with a 150Ohm Resistor and a 5V Power Supply. (actual voltage supply as measured was 4.5Volts)

Values:
Voltage Supply: 4.5 Volts
150 Ohm Resister: 2.42 Volts
Grn LED: 2.11Volts.

Voltage drop across the entire circuit as a Sum:

-4.5V + 2.42V + 2.11V = 0