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.

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Age band:Ages 13-15 Ages 16-18

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Worksheet StudioPractice pack · Ages 16-18

Transformer turns & voltage ratio

Take your time. Show your thinking.

1. An ideal step-up transformer has 100 primary turns and 400 secondary turns. If the primary voltage is 120 V, what is the secondary voltage?
120V · 100T · ? V · 400T
2. An ideal step-up transformer has 750 primary turns and 1500 secondary turns. If the primary voltage is 170 V, what is the secondary voltage?
170V · 750T · ? V · 1500T
3. An ideal step-up transformer has 800 primary turns and 5600 secondary turns. If the primary voltage is 220 V, what is the secondary voltage?
220V · 800T · ? V · 5600T
4. An ideal step-up transformer has 800 primary turns and 6400 secondary turns. If the primary voltage is 210 V, what is the secondary voltage?
210V · 800T · ? V · 6400T
5. An ideal step-up transformer has 350 primary turns and 1750 secondary turns. If the primary voltage is 170 V, what is the secondary voltage?
170V · 350T · ? V · 1750T
6. An ideal step-up transformer has 300 primary turns and 1500 secondary turns. If the primary voltage is 70 V, what is the secondary voltage?
70V · 300T · ? V · 1500T
7. An ideal step-up transformer has 1000 primary turns and 3000 secondary turns. If the primary voltage is 100 V, what is the secondary voltage?
100V · 1000T · ? V · 3000T
8. An ideal step-up transformer has 1000 primary turns and 3000 secondary turns. If the primary voltage is 140 V, what is the secondary voltage?
140V · 1000T · ? V · 3000T
9. An ideal step-up transformer has 850 primary turns and 2550 secondary turns. If the primary voltage is 200 V, what is the secondary voltage?
200V · 850T · ? V · 2550T
10. An ideal step-up transformer has 1100 primary turns and 8800 secondary turns. If the primary voltage is 70 V, what is the secondary voltage?
70V · 1100T · ? V · 8800T
11. An ideal step-up transformer has 750 primary turns and 3000 secondary turns. If the primary voltage is 120 V, what is the secondary voltage?
120V · 750T · ? V · 3000T
12. An ideal step-up transformer has 450 primary turns and 2250 secondary turns. If the primary voltage is 230 V, what is the secondary voltage?
230V · 450T · ? V · 2250T

12 questions · Seed 51 · 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 100 primary turns and 400 secondary turns. If the primary voltage is 120 V, what is the secondary voltage?
480 V
Vs = Vp × (Ns ÷ Np) = 120 × (400 ÷ 100) = 480 V.
2. An ideal step-up transformer has 750 primary turns and 1500 secondary turns. If the primary voltage is 170 V, what is the secondary voltage?
340 V
Vs = Vp × (Ns ÷ Np) = 170 × (1500 ÷ 750) = 340 V.
3. An ideal step-up transformer has 800 primary turns and 5600 secondary turns. If the primary voltage is 220 V, what is the secondary voltage?
1540 V
Vs = Vp × (Ns ÷ Np) = 220 × (5600 ÷ 800) = 1540 V.
4. An ideal step-up transformer has 800 primary turns and 6400 secondary turns. If the primary voltage is 210 V, what is the secondary voltage?
1680 V
Vs = Vp × (Ns ÷ Np) = 210 × (6400 ÷ 800) = 1680 V.
5. An ideal step-up transformer has 350 primary turns and 1750 secondary turns. If the primary voltage is 170 V, what is the secondary voltage?
850 V
Vs = Vp × (Ns ÷ Np) = 170 × (1750 ÷ 350) = 850 V.
6. An ideal step-up transformer has 300 primary turns and 1500 secondary turns. If the primary voltage is 70 V, what is the secondary voltage?
350 V
Vs = Vp × (Ns ÷ Np) = 70 × (1500 ÷ 300) = 350 V.
7. An ideal step-up transformer has 1000 primary turns and 3000 secondary turns. If the primary voltage is 100 V, what is the secondary voltage?
300 V
Vs = Vp × (Ns ÷ Np) = 100 × (3000 ÷ 1000) = 300 V.
8. An ideal step-up transformer has 1000 primary turns and 3000 secondary turns. If the primary voltage is 140 V, what is the secondary voltage?
420 V
Vs = Vp × (Ns ÷ Np) = 140 × (3000 ÷ 1000) = 420 V.
9. An ideal step-up transformer has 850 primary turns and 2550 secondary turns. If the primary voltage is 200 V, what is the secondary voltage?
600 V
Vs = Vp × (Ns ÷ Np) = 200 × (2550 ÷ 850) = 600 V.
10. An ideal step-up transformer has 1100 primary turns and 8800 secondary turns. If the primary voltage is 70 V, what is the secondary voltage?
560 V
Vs = Vp × (Ns ÷ Np) = 70 × (8800 ÷ 1100) = 560 V.
11. An ideal step-up transformer has 750 primary turns and 3000 secondary turns. If the primary voltage is 120 V, what is the secondary voltage?
480 V
Vs = Vp × (Ns ÷ Np) = 120 × (3000 ÷ 750) = 480 V.
12. An ideal step-up transformer has 450 primary turns and 2250 secondary turns. If the primary voltage is 230 V, what is the secondary voltage?
1150 V
Vs = Vp × (Ns ÷ Np) = 230 × (2250 ÷ 450) = 1150 V.

12 questions · Seed 51 · 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 100 primary turns and 400 secondary turns. If the primary voltage is 120 V, what is the secondary voltage?
120V · 100T · ? V · 400T
2. An ideal step-up transformer has 750 primary turns and 1500 secondary turns. If the primary voltage is 170 V, what is the secondary voltage?
170V · 750T · ? V · 1500T
3. An ideal step-up transformer has 800 primary turns and 5600 secondary turns. If the primary voltage is 220 V, what is the secondary voltage?
220V · 800T · ? V · 5600T
4. An ideal step-up transformer has 800 primary turns and 6400 secondary turns. If the primary voltage is 210 V, what is the secondary voltage?
210V · 800T · ? V · 6400T
5. An ideal step-up transformer has 350 primary turns and 1750 secondary turns. If the primary voltage is 170 V, what is the secondary voltage?
170V · 350T · ? V · 1750T
6. An ideal step-up transformer has 300 primary turns and 1500 secondary turns. If the primary voltage is 70 V, what is the secondary voltage?
70V · 300T · ? V · 1500T
7. An ideal step-up transformer has 1000 primary turns and 3000 secondary turns. If the primary voltage is 100 V, what is the secondary voltage?
100V · 1000T · ? V · 3000T
8. An ideal step-up transformer has 1000 primary turns and 3000 secondary turns. If the primary voltage is 140 V, what is the secondary voltage?
140V · 1000T · ? V · 3000T
9. An ideal step-up transformer has 850 primary turns and 2550 secondary turns. If the primary voltage is 200 V, what is the secondary voltage?
200V · 850T · ? V · 2550T
10. An ideal step-up transformer has 1100 primary turns and 8800 secondary turns. If the primary voltage is 70 V, what is the secondary voltage?
70V · 1100T · ? V · 8800T
11. An ideal step-up transformer has 750 primary turns and 3000 secondary turns. If the primary voltage is 120 V, what is the secondary voltage?
120V · 750T · ? V · 3000T
12. An ideal step-up transformer has 450 primary turns and 2250 secondary turns. If the primary voltage is 230 V, what is the secondary voltage?
230V · 450T · ? V · 2250T

12 questions · Seed 51 · 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 100 primary turns and 400 secondary turns. If the primary voltage is 120 V, what is the secondary voltage?
480 V
Vs = Vp × (Ns ÷ Np) = 120 × (400 ÷ 100) = 480 V.
2. An ideal step-up transformer has 750 primary turns and 1500 secondary turns. If the primary voltage is 170 V, what is the secondary voltage?
340 V
Vs = Vp × (Ns ÷ Np) = 170 × (1500 ÷ 750) = 340 V.
3. An ideal step-up transformer has 800 primary turns and 5600 secondary turns. If the primary voltage is 220 V, what is the secondary voltage?
1540 V
Vs = Vp × (Ns ÷ Np) = 220 × (5600 ÷ 800) = 1540 V.
4. An ideal step-up transformer has 800 primary turns and 6400 secondary turns. If the primary voltage is 210 V, what is the secondary voltage?
1680 V
Vs = Vp × (Ns ÷ Np) = 210 × (6400 ÷ 800) = 1680 V.
5. An ideal step-up transformer has 350 primary turns and 1750 secondary turns. If the primary voltage is 170 V, what is the secondary voltage?
850 V
Vs = Vp × (Ns ÷ Np) = 170 × (1750 ÷ 350) = 850 V.
6. An ideal step-up transformer has 300 primary turns and 1500 secondary turns. If the primary voltage is 70 V, what is the secondary voltage?
350 V
Vs = Vp × (Ns ÷ Np) = 70 × (1500 ÷ 300) = 350 V.
7. An ideal step-up transformer has 1000 primary turns and 3000 secondary turns. If the primary voltage is 100 V, what is the secondary voltage?
300 V
Vs = Vp × (Ns ÷ Np) = 100 × (3000 ÷ 1000) = 300 V.
8. An ideal step-up transformer has 1000 primary turns and 3000 secondary turns. If the primary voltage is 140 V, what is the secondary voltage?
420 V
Vs = Vp × (Ns ÷ Np) = 140 × (3000 ÷ 1000) = 420 V.
9. An ideal step-up transformer has 850 primary turns and 2550 secondary turns. If the primary voltage is 200 V, what is the secondary voltage?
600 V
Vs = Vp × (Ns ÷ Np) = 200 × (2550 ÷ 850) = 600 V.
10. An ideal step-up transformer has 1100 primary turns and 8800 secondary turns. If the primary voltage is 70 V, what is the secondary voltage?
560 V
Vs = Vp × (Ns ÷ Np) = 70 × (8800 ÷ 1100) = 560 V.
11. An ideal step-up transformer has 750 primary turns and 3000 secondary turns. If the primary voltage is 120 V, what is the secondary voltage?
480 V
Vs = Vp × (Ns ÷ Np) = 120 × (3000 ÷ 750) = 480 V.
12. An ideal step-up transformer has 450 primary turns and 2250 secondary turns. If the primary voltage is 230 V, what is the secondary voltage?
1150 V
Vs = Vp × (Ns ÷ Np) = 230 × (2250 ÷ 450) = 1150 V.

12 questions · Seed 51 · Age guidance, not curriculum certification