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_{L}in 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_{L}on the secondary voltage.
The secondary voltage equals RL times Is.
- Describe the relationship of R_{L}on 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.