ScienceAges 13-15

Transformer turns & voltage ratio

Use the ideal transformer ratio Vs ÷ Vp = Ns ÷ Np to calculate secondary output voltage. Review suitability for your learners before teaching.

New variation Try interactive challenge Browse templates

Age band:Ages 13-15 Ages 16-18

Choose “Save as PDF” to keep a copy. Use your browser’s paper setting for A4 or Letter.

Worksheet StudioPractice pack · Ages 13-15

Transformer turns & voltage ratio

Take your time. Show your thinking.

1. An ideal step-up transformer has 950 primary turns and 4750 secondary turns. If the primary voltage is 100 V, what is the secondary voltage?
100V · 950T · ? V · 4750T
2. An ideal step-up transformer has 1100 primary turns and 7700 secondary turns. If the primary voltage is 220 V, what is the secondary voltage?
220V · 1100T · ? V · 7700T
3. An ideal step-up transformer has 1150 primary turns and 4600 secondary turns. If the primary voltage is 50 V, what is the secondary voltage?
50V · 1150T · ? V · 4600T
4. An ideal step-up transformer has 650 primary turns and 2600 secondary turns. If the primary voltage is 120 V, what is the secondary voltage?
120V · 650T · ? V · 2600T
5. An ideal step-up transformer has 750 primary turns and 4500 secondary turns. If the primary voltage is 30 V, what is the secondary voltage?
30V · 750T · ? V · 4500T
6. An ideal step-up transformer has 500 primary turns and 3500 secondary turns. If the primary voltage is 200 V, what is the secondary voltage?
200V · 500T · ? V · 3500T
7. An ideal step-up transformer has 250 primary turns and 1500 secondary turns. If the primary voltage is 230 V, what is the secondary voltage?
230V · 250T · ? V · 1500T
8. An ideal step-up transformer has 1000 primary turns and 6000 secondary turns. If the primary voltage is 20 V, what is the secondary voltage?
20V · 1000T · ? V · 6000T
9. An ideal step-up transformer has 1300 primary turns and 9100 secondary turns. If the primary voltage is 140 V, what is the secondary voltage?
140V · 1300T · ? V · 9100T
10. An ideal step-up transformer has 1300 primary turns and 5200 secondary turns. If the primary voltage is 220 V, what is the secondary voltage?
220V · 1300T · ? V · 5200T
11. An ideal step-up transformer has 1250 primary turns and 5000 secondary turns. If the primary voltage is 120 V, what is the secondary voltage?
120V · 1250T · ? V · 5000T
12. An ideal step-up transformer has 1250 primary turns and 6250 secondary turns. If the primary voltage is 80 V, what is the secondary voltage?
80V · 1250T · ? V · 6250T

12 questions · Seed 43 · Age guidance, not curriculum certification

View the answer key

Worksheet StudioAnswer key · Ages 13-15

Transformer turns & voltage ratio

Answers and reasoning. Review before teaching.

1. An ideal step-up transformer has 950 primary turns and 4750 secondary turns. If the primary voltage is 100 V, what is the secondary voltage?
500 V
Vs = Vp × (Ns ÷ Np) = 100 × (4750 ÷ 950) = 500 V.
2. An ideal step-up transformer has 1100 primary turns and 7700 secondary turns. If the primary voltage is 220 V, what is the secondary voltage?
1540 V
Vs = Vp × (Ns ÷ Np) = 220 × (7700 ÷ 1100) = 1540 V.
3. An ideal step-up transformer has 1150 primary turns and 4600 secondary turns. If the primary voltage is 50 V, what is the secondary voltage?
200 V
Vs = Vp × (Ns ÷ Np) = 50 × (4600 ÷ 1150) = 200 V.
4. An ideal step-up transformer has 650 primary turns and 2600 secondary turns. If the primary voltage is 120 V, what is the secondary voltage?
480 V
Vs = Vp × (Ns ÷ Np) = 120 × (2600 ÷ 650) = 480 V.
5. An ideal step-up transformer has 750 primary turns and 4500 secondary turns. If the primary voltage is 30 V, what is the secondary voltage?
180 V
Vs = Vp × (Ns ÷ Np) = 30 × (4500 ÷ 750) = 180 V.
6. An ideal step-up transformer has 500 primary turns and 3500 secondary turns. If the primary voltage is 200 V, what is the secondary voltage?
1400 V
Vs = Vp × (Ns ÷ Np) = 200 × (3500 ÷ 500) = 1400 V.
7. An ideal step-up transformer has 250 primary turns and 1500 secondary turns. If the primary voltage is 230 V, what is the secondary voltage?
1380 V
Vs = Vp × (Ns ÷ Np) = 230 × (1500 ÷ 250) = 1380 V.
8. An ideal step-up transformer has 1000 primary turns and 6000 secondary turns. If the primary voltage is 20 V, what is the secondary voltage?
120 V
Vs = Vp × (Ns ÷ Np) = 20 × (6000 ÷ 1000) = 120 V.
9. An ideal step-up transformer has 1300 primary turns and 9100 secondary turns. If the primary voltage is 140 V, what is the secondary voltage?
980 V
Vs = Vp × (Ns ÷ Np) = 140 × (9100 ÷ 1300) = 980 V.
10. An ideal step-up transformer has 1300 primary turns and 5200 secondary turns. If the primary voltage is 220 V, what is the secondary voltage?
880 V
Vs = Vp × (Ns ÷ Np) = 220 × (5200 ÷ 1300) = 880 V.
11. An ideal step-up transformer has 1250 primary turns and 5000 secondary turns. If the primary voltage is 120 V, what is the secondary voltage?
480 V
Vs = Vp × (Ns ÷ Np) = 120 × (5000 ÷ 1250) = 480 V.
12. An ideal step-up transformer has 1250 primary turns and 6250 secondary turns. If the primary voltage is 80 V, what is the secondary voltage?
400 V
Vs = Vp × (Ns ÷ Np) = 80 × (6250 ÷ 1250) = 400 V.

12 questions · Seed 43 · Age guidance, not curriculum certification

Worksheet StudioPractice pack · Ages 13-15

Transformer turns & voltage ratio

Take your time. Show your thinking.

1. An ideal step-up transformer has 950 primary turns and 4750 secondary turns. If the primary voltage is 100 V, what is the secondary voltage?
100V · 950T · ? V · 4750T
2. An ideal step-up transformer has 1100 primary turns and 7700 secondary turns. If the primary voltage is 220 V, what is the secondary voltage?
220V · 1100T · ? V · 7700T
3. An ideal step-up transformer has 1150 primary turns and 4600 secondary turns. If the primary voltage is 50 V, what is the secondary voltage?
50V · 1150T · ? V · 4600T
4. An ideal step-up transformer has 650 primary turns and 2600 secondary turns. If the primary voltage is 120 V, what is the secondary voltage?
120V · 650T · ? V · 2600T
5. An ideal step-up transformer has 750 primary turns and 4500 secondary turns. If the primary voltage is 30 V, what is the secondary voltage?
30V · 750T · ? V · 4500T
6. An ideal step-up transformer has 500 primary turns and 3500 secondary turns. If the primary voltage is 200 V, what is the secondary voltage?
200V · 500T · ? V · 3500T
7. An ideal step-up transformer has 250 primary turns and 1500 secondary turns. If the primary voltage is 230 V, what is the secondary voltage?
230V · 250T · ? V · 1500T
8. An ideal step-up transformer has 1000 primary turns and 6000 secondary turns. If the primary voltage is 20 V, what is the secondary voltage?
20V · 1000T · ? V · 6000T
9. An ideal step-up transformer has 1300 primary turns and 9100 secondary turns. If the primary voltage is 140 V, what is the secondary voltage?
140V · 1300T · ? V · 9100T
10. An ideal step-up transformer has 1300 primary turns and 5200 secondary turns. If the primary voltage is 220 V, what is the secondary voltage?
220V · 1300T · ? V · 5200T
11. An ideal step-up transformer has 1250 primary turns and 5000 secondary turns. If the primary voltage is 120 V, what is the secondary voltage?
120V · 1250T · ? V · 5000T
12. An ideal step-up transformer has 1250 primary turns and 6250 secondary turns. If the primary voltage is 80 V, what is the secondary voltage?
80V · 1250T · ? V · 6250T

12 questions · Seed 43 · Age guidance, not curriculum certification

Worksheet StudioAnswer key · Ages 13-15

Transformer turns & voltage ratio

Answers and reasoning. Review before teaching.

1. An ideal step-up transformer has 950 primary turns and 4750 secondary turns. If the primary voltage is 100 V, what is the secondary voltage?
500 V
Vs = Vp × (Ns ÷ Np) = 100 × (4750 ÷ 950) = 500 V.
2. An ideal step-up transformer has 1100 primary turns and 7700 secondary turns. If the primary voltage is 220 V, what is the secondary voltage?
1540 V
Vs = Vp × (Ns ÷ Np) = 220 × (7700 ÷ 1100) = 1540 V.
3. An ideal step-up transformer has 1150 primary turns and 4600 secondary turns. If the primary voltage is 50 V, what is the secondary voltage?
200 V
Vs = Vp × (Ns ÷ Np) = 50 × (4600 ÷ 1150) = 200 V.
4. An ideal step-up transformer has 650 primary turns and 2600 secondary turns. If the primary voltage is 120 V, what is the secondary voltage?
480 V
Vs = Vp × (Ns ÷ Np) = 120 × (2600 ÷ 650) = 480 V.
5. An ideal step-up transformer has 750 primary turns and 4500 secondary turns. If the primary voltage is 30 V, what is the secondary voltage?
180 V
Vs = Vp × (Ns ÷ Np) = 30 × (4500 ÷ 750) = 180 V.
6. An ideal step-up transformer has 500 primary turns and 3500 secondary turns. If the primary voltage is 200 V, what is the secondary voltage?
1400 V
Vs = Vp × (Ns ÷ Np) = 200 × (3500 ÷ 500) = 1400 V.
7. An ideal step-up transformer has 250 primary turns and 1500 secondary turns. If the primary voltage is 230 V, what is the secondary voltage?
1380 V
Vs = Vp × (Ns ÷ Np) = 230 × (1500 ÷ 250) = 1380 V.
8. An ideal step-up transformer has 1000 primary turns and 6000 secondary turns. If the primary voltage is 20 V, what is the secondary voltage?
120 V
Vs = Vp × (Ns ÷ Np) = 20 × (6000 ÷ 1000) = 120 V.
9. An ideal step-up transformer has 1300 primary turns and 9100 secondary turns. If the primary voltage is 140 V, what is the secondary voltage?
980 V
Vs = Vp × (Ns ÷ Np) = 140 × (9100 ÷ 1300) = 980 V.
10. An ideal step-up transformer has 1300 primary turns and 5200 secondary turns. If the primary voltage is 220 V, what is the secondary voltage?
880 V
Vs = Vp × (Ns ÷ Np) = 220 × (5200 ÷ 1300) = 880 V.
11. An ideal step-up transformer has 1250 primary turns and 5000 secondary turns. If the primary voltage is 120 V, what is the secondary voltage?
480 V
Vs = Vp × (Ns ÷ Np) = 120 × (5000 ÷ 1250) = 480 V.
12. An ideal step-up transformer has 1250 primary turns and 6250 secondary turns. If the primary voltage is 80 V, what is the secondary voltage?
400 V
Vs = Vp × (Ns ÷ Np) = 80 × (6250 ÷ 1250) = 400 V.

12 questions · Seed 43 · Age guidance, not curriculum certification