Variable dc power supply multisim

Procedure:

Open Multisim Software

Program Files -> National Instruments (folder) -> Circuit Design Suite -> Multisim

START A NEW PROJECT BY GOING TO FILE>NEW>NI ELVIS I Design. You will get a workspace that has the connections you will find on our ELVIS board. Later we will see a 3-D Model of the ELVIS Board.

On every Design sheet from the top menu “Place” find “Text” and write your:

Name

ENGR 2140A

Date

YOU WILL LOSE POINTS FOR EVERY CIRCUIT IMAGE THAT DOES NOT HAVE THIS

Part 1: Build a Voltage Divider and Test it with Loads.

Construct a voltage divider with a 12V source and use 1000, 2000 and 3000 Ohms to divide the voltage into 10V and 6V at nodes in the circuit. Va, Vb, Vc are the connection points you will use to load to the circuit at 12, 10 and 6V. You will want to put voltage indicators on each one connected between ground and each test point. This will save you time when you put the load on the circuit, to see the voltage change at the connection point when you add a load. To get the 12 V source, can go to Simulate > Instruments >NI ELVIS mx instruments > NI ElVIS Variable Power Supply just like you would see in the ELVIS Instrument panel. But to simplify this circuit INSTEAD USE DC POWER SUPPLY FOR 12V SO YOU HAVE A BATTERY ON THE BOARD. This will make the 3-D circuit construction easier later.

Insert the image of your voltage divider circuit here. It does not need the extra labels that mine has, but make sure the voltage indicators are included and show that you have the correct voltages. Do NOT have a load resistor yet on this circuit:

To load the circuit you will place one resistor between ground and either Va, Vb or Vc. You will only have one load resistor on the circuit at any one time, unused connection points remain unattached!!!

You can use Excel to do the calculations to save time filling in the chart.

Location to measure Voltage

Load Resistor connected at that location

Expected voltage (with no load)

Measured voltage (with specified load)

% difference (Difference divided by expected)

Power delivered to load resistor using measured voltage.

P = (V^2)/R

Vc

1kOhm

6 V

Vc

4.7 kOhm

6 V

Vc

10 kOhm

6 V

Vc

20 kOhm

6 V

Vc

100 kOhm

6 V

Vb

1kOhm

10 V

Vb

4.7 kOhm

10 V

Vb

10 kOhm

10 V

Vb

20 kOhm

10 V

Vb

100 kOhm

10 V

Va

1kOhm

12 V

Va

4.7 kOhm

12 V

Va

10 kOhm

12 V

Va

20 kOhm

12 V

Va

100 kOhm

12 V

Which load affected the voltage divider the most (highest % difference)? ____________________

Why? ________________________________________________________________________

Which load value resulted in the highest power dissipated in the load resistor at Va?_____________

Why? _______________________________________________________________________________

Which load value resulted in the highest power dissipated in the load resistor at Vb? ____________

Which load value resulted in the highest power dissipated in the load resistor at Vc?_____________

Is it the same load resistor for max power transfer for Vb and Vc? _________________

We will eventually learn how to calculate the load resistance that allows maximum power transfer. But for now, you should see that if the battery is not controlling the voltage directly, adding a load to a voltage divider changes the circuit, and each connection point in the voltage divider has a different load resistance value for maximum power transfer.

USE EXCEL TO MAKE A GRAPH OF THE DATA IN YOU COLLECTED TH