Transformers Sample Assignment

Transformers

1. The turns ratio modified to 20:1, calculate the following values of Vs and Is for the given values of R_Lin the table below:

R_L	Calculated Vs	Calculated Is	Measured Vs	Measured Is
0 Ω	120Vrms/20:1 = 6Vrms	6Vrms/0ohms= 0A	05.99Vac	-r-
10 Ω	120Vrms/20:1 = 6Vrms	6Vrms/10ohms= 600mA	05.99Vac	599.97mA
25 Ω	120Vrms/20:1 = 6Vrms	6Vrms/25ohms= 240mA	05.99Vac	239.991mA
50 Ω	120Vrms/20:1 = 6Vrms	6Vrms/50ohms= 120mA	05.99Vac	119.995mA
100 Ω	120Vrms/20:1 = 6Vrms	6Vrms/100ohms= 60mA	05.99Vac	59.998mA
1000 Ω	120Vrms/20:1 = 6Vrms	6Vrms/1000ohms= 6mA	05.99Vac	6mA

2. Construct the transformer circuit in MultiSIM and complete the table in part 2 with the measured values of Vs and Is for each value of R_L. Use the Agilent Digital Multi-meter to take the measurements and capture a screen shot of each measurement.

3. Discuss the following:

Describe the relationship of R_Lon the secondary voltage.

The secondary voltage equals RL times Is.

Describe the relationship of R_Lon the secondary current.
The secondary current equals secondary voltage divided by RL
How do the calculated values compare to the measured values?
Yes, although I can get a 0A when resistor equals 0 but when measuring I get –r- or overload reading. Np/Ns = Vp/Vs.
How would you go about calculating the transformer power efficiency?
Efficiency = (Vs*Is)/(Vp*Ip)
How would you go about measuring the transformer power efficiency?
Put 2 wattmeter on both ends of the transformer (on the primary and on the secondary). Divide the output of power of primary by the input power of the secondary.
Determine the transformer power efficiency for the circuit in MultiSIM. Include a calculation and a measured value.
Efficiency = (Vs*Is)/(Vp*Ip)= (5.99*0.599)/(120*0.030) = (3.58/3.60)

= 99.44%

Include all calculations, screenshots of measurements, the table results of part 2 and the answers to part 4 in a word processing document and submit as EE115W4LabYourGID.docx, or an equivalent word processing file extension.