ScienceAges 16-18

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 16-18

Transformer turns & voltage ratio

Take your time. Show your thinking.

1. An ideal step-up transformer has 400 primary turns and 2400 secondary turns. If the primary voltage is 70 V, what is the secondary voltage?
70V · 400T · ? V · 2400T
2. An ideal step-up transformer has 550 primary turns and 2750 secondary turns. If the primary voltage is 220 V, what is the secondary voltage?
220V · 550T · ? V · 2750T
3. An ideal step-up transformer has 1400 primary turns and 5600 secondary turns. If the primary voltage is 50 V, what is the secondary voltage?
50V · 1400T · ? V · 5600T
4. An ideal step-up transformer has 350 primary turns and 1750 secondary turns. If the primary voltage is 180 V, what is the secondary voltage?
180V · 350T · ? V · 1750T
5. An ideal step-up transformer has 1450 primary turns and 7250 secondary turns. If the primary voltage is 60 V, what is the secondary voltage?
60V · 1450T · ? V · 7250T
6. An ideal step-up transformer has 200 primary turns and 400 secondary turns. If the primary voltage is 220 V, what is the secondary voltage?
220V · 200T · ? V · 400T
7. An ideal step-up transformer has 400 primary turns and 1600 secondary turns. If the primary voltage is 50 V, what is the secondary voltage?
50V · 400T · ? V · 1600T
8. An ideal step-up transformer has 250 primary turns and 2000 secondary turns. If the primary voltage is 90 V, what is the secondary voltage?
90V · 250T · ? V · 2000T
9. An ideal step-up transformer has 1150 primary turns and 5750 secondary turns. If the primary voltage is 240 V, what is the secondary voltage?
240V · 1150T · ? V · 5750T
10. An ideal step-up transformer has 1250 primary turns and 3750 secondary turns. If the primary voltage is 100 V, what is the secondary voltage?
100V · 1250T · ? V · 3750T
11. An ideal step-up transformer has 1050 primary turns and 7350 secondary turns. If the primary voltage is 70 V, what is the secondary voltage?
70V · 1050T · ? V · 7350T
12. An ideal step-up transformer has 1100 primary turns and 5500 secondary turns. If the primary voltage is 170 V, what is the secondary voltage?
170V · 1100T · ? V · 5500T

12 questions · Seed 46 · Age guidance, not curriculum certification

View the answer key

Worksheet StudioAnswer key · Ages 16-18

Transformer turns & voltage ratio

Answers and reasoning. Review before teaching.

1. An ideal step-up transformer has 400 primary turns and 2400 secondary turns. If the primary voltage is 70 V, what is the secondary voltage?
420 V
Vs = Vp × (Ns ÷ Np) = 70 × (2400 ÷ 400) = 420 V.
2. An ideal step-up transformer has 550 primary turns and 2750 secondary turns. If the primary voltage is 220 V, what is the secondary voltage?
1100 V
Vs = Vp × (Ns ÷ Np) = 220 × (2750 ÷ 550) = 1100 V.
3. An ideal step-up transformer has 1400 primary turns and 5600 secondary turns. If the primary voltage is 50 V, what is the secondary voltage?
200 V
Vs = Vp × (Ns ÷ Np) = 50 × (5600 ÷ 1400) = 200 V.
4. An ideal step-up transformer has 350 primary turns and 1750 secondary turns. If the primary voltage is 180 V, what is the secondary voltage?
900 V
Vs = Vp × (Ns ÷ Np) = 180 × (1750 ÷ 350) = 900 V.
5. An ideal step-up transformer has 1450 primary turns and 7250 secondary turns. If the primary voltage is 60 V, what is the secondary voltage?
300 V
Vs = Vp × (Ns ÷ Np) = 60 × (7250 ÷ 1450) = 300 V.
6. An ideal step-up transformer has 200 primary turns and 400 secondary turns. If the primary voltage is 220 V, what is the secondary voltage?
440 V
Vs = Vp × (Ns ÷ Np) = 220 × (400 ÷ 200) = 440 V.
7. An ideal step-up transformer has 400 primary turns and 1600 secondary turns. If the primary voltage is 50 V, what is the secondary voltage?
200 V
Vs = Vp × (Ns ÷ Np) = 50 × (1600 ÷ 400) = 200 V.
8. An ideal step-up transformer has 250 primary turns and 2000 secondary turns. If the primary voltage is 90 V, what is the secondary voltage?
720 V
Vs = Vp × (Ns ÷ Np) = 90 × (2000 ÷ 250) = 720 V.
9. An ideal step-up transformer has 1150 primary turns and 5750 secondary turns. If the primary voltage is 240 V, what is the secondary voltage?
1200 V
Vs = Vp × (Ns ÷ Np) = 240 × (5750 ÷ 1150) = 1200 V.
10. An ideal step-up transformer has 1250 primary turns and 3750 secondary turns. If the primary voltage is 100 V, what is the secondary voltage?
300 V
Vs = Vp × (Ns ÷ Np) = 100 × (3750 ÷ 1250) = 300 V.
11. An ideal step-up transformer has 1050 primary turns and 7350 secondary turns. If the primary voltage is 70 V, what is the secondary voltage?
490 V
Vs = Vp × (Ns ÷ Np) = 70 × (7350 ÷ 1050) = 490 V.
12. An ideal step-up transformer has 1100 primary turns and 5500 secondary turns. If the primary voltage is 170 V, what is the secondary voltage?
850 V
Vs = Vp × (Ns ÷ Np) = 170 × (5500 ÷ 1100) = 850 V.

12 questions · Seed 46 · Age guidance, not curriculum certification

Worksheet StudioPractice pack · Ages 16-18

Transformer turns & voltage ratio

Take your time. Show your thinking.

1. An ideal step-up transformer has 400 primary turns and 2400 secondary turns. If the primary voltage is 70 V, what is the secondary voltage?
70V · 400T · ? V · 2400T
2. An ideal step-up transformer has 550 primary turns and 2750 secondary turns. If the primary voltage is 220 V, what is the secondary voltage?
220V · 550T · ? V · 2750T
3. An ideal step-up transformer has 1400 primary turns and 5600 secondary turns. If the primary voltage is 50 V, what is the secondary voltage?
50V · 1400T · ? V · 5600T
4. An ideal step-up transformer has 350 primary turns and 1750 secondary turns. If the primary voltage is 180 V, what is the secondary voltage?
180V · 350T · ? V · 1750T
5. An ideal step-up transformer has 1450 primary turns and 7250 secondary turns. If the primary voltage is 60 V, what is the secondary voltage?
60V · 1450T · ? V · 7250T
6. An ideal step-up transformer has 200 primary turns and 400 secondary turns. If the primary voltage is 220 V, what is the secondary voltage?
220V · 200T · ? V · 400T
7. An ideal step-up transformer has 400 primary turns and 1600 secondary turns. If the primary voltage is 50 V, what is the secondary voltage?
50V · 400T · ? V · 1600T
8. An ideal step-up transformer has 250 primary turns and 2000 secondary turns. If the primary voltage is 90 V, what is the secondary voltage?
90V · 250T · ? V · 2000T
9. An ideal step-up transformer has 1150 primary turns and 5750 secondary turns. If the primary voltage is 240 V, what is the secondary voltage?
240V · 1150T · ? V · 5750T
10. An ideal step-up transformer has 1250 primary turns and 3750 secondary turns. If the primary voltage is 100 V, what is the secondary voltage?
100V · 1250T · ? V · 3750T
11. An ideal step-up transformer has 1050 primary turns and 7350 secondary turns. If the primary voltage is 70 V, what is the secondary voltage?
70V · 1050T · ? V · 7350T
12. An ideal step-up transformer has 1100 primary turns and 5500 secondary turns. If the primary voltage is 170 V, what is the secondary voltage?
170V · 1100T · ? V · 5500T

12 questions · Seed 46 · Age guidance, not curriculum certification

Worksheet StudioAnswer key · Ages 16-18

Transformer turns & voltage ratio

Answers and reasoning. Review before teaching.

1. An ideal step-up transformer has 400 primary turns and 2400 secondary turns. If the primary voltage is 70 V, what is the secondary voltage?
420 V
Vs = Vp × (Ns ÷ Np) = 70 × (2400 ÷ 400) = 420 V.
2. An ideal step-up transformer has 550 primary turns and 2750 secondary turns. If the primary voltage is 220 V, what is the secondary voltage?
1100 V
Vs = Vp × (Ns ÷ Np) = 220 × (2750 ÷ 550) = 1100 V.
3. An ideal step-up transformer has 1400 primary turns and 5600 secondary turns. If the primary voltage is 50 V, what is the secondary voltage?
200 V
Vs = Vp × (Ns ÷ Np) = 50 × (5600 ÷ 1400) = 200 V.
4. An ideal step-up transformer has 350 primary turns and 1750 secondary turns. If the primary voltage is 180 V, what is the secondary voltage?
900 V
Vs = Vp × (Ns ÷ Np) = 180 × (1750 ÷ 350) = 900 V.
5. An ideal step-up transformer has 1450 primary turns and 7250 secondary turns. If the primary voltage is 60 V, what is the secondary voltage?
300 V
Vs = Vp × (Ns ÷ Np) = 60 × (7250 ÷ 1450) = 300 V.
6. An ideal step-up transformer has 200 primary turns and 400 secondary turns. If the primary voltage is 220 V, what is the secondary voltage?
440 V
Vs = Vp × (Ns ÷ Np) = 220 × (400 ÷ 200) = 440 V.
7. An ideal step-up transformer has 400 primary turns and 1600 secondary turns. If the primary voltage is 50 V, what is the secondary voltage?
200 V
Vs = Vp × (Ns ÷ Np) = 50 × (1600 ÷ 400) = 200 V.
8. An ideal step-up transformer has 250 primary turns and 2000 secondary turns. If the primary voltage is 90 V, what is the secondary voltage?
720 V
Vs = Vp × (Ns ÷ Np) = 90 × (2000 ÷ 250) = 720 V.
9. An ideal step-up transformer has 1150 primary turns and 5750 secondary turns. If the primary voltage is 240 V, what is the secondary voltage?
1200 V
Vs = Vp × (Ns ÷ Np) = 240 × (5750 ÷ 1150) = 1200 V.
10. An ideal step-up transformer has 1250 primary turns and 3750 secondary turns. If the primary voltage is 100 V, what is the secondary voltage?
300 V
Vs = Vp × (Ns ÷ Np) = 100 × (3750 ÷ 1250) = 300 V.
11. An ideal step-up transformer has 1050 primary turns and 7350 secondary turns. If the primary voltage is 70 V, what is the secondary voltage?
490 V
Vs = Vp × (Ns ÷ Np) = 70 × (7350 ÷ 1050) = 490 V.
12. An ideal step-up transformer has 1100 primary turns and 5500 secondary turns. If the primary voltage is 170 V, what is the secondary voltage?
850 V
Vs = Vp × (Ns ÷ Np) = 170 × (5500 ÷ 1100) = 850 V.

12 questions · Seed 46 · Age guidance, not curriculum certification