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.

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Age band:Ages 13-15 Ages 16-18

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Worksheet StudioPractice pack · Ages 13-15

Transformer turns & voltage ratio

Take your time. Show your thinking.

1. An ideal step-up transformer has 150 primary turns and 750 secondary turns. If the primary voltage is 40 V, what is the secondary voltage?
40V · 150T · ? V · 750T
2. An ideal step-up transformer has 1500 primary turns and 7500 secondary turns. If the primary voltage is 160 V, what is the secondary voltage?
160V · 1500T · ? V · 7500T
3. An ideal step-up transformer has 1400 primary turns and 7000 secondary turns. If the primary voltage is 140 V, what is the secondary voltage?
140V · 1400T · ? V · 7000T
4. An ideal step-up transformer has 1200 primary turns and 9600 secondary turns. If the primary voltage is 170 V, what is the secondary voltage?
170V · 1200T · ? V · 9600T
5. An ideal step-up transformer has 1050 primary turns and 7350 secondary turns. If the primary voltage is 20 V, what is the secondary voltage?
20V · 1050T · ? V · 7350T
6. An ideal step-up transformer has 1100 primary turns and 8800 secondary turns. If the primary voltage is 50 V, what is the secondary voltage?
50V · 1100T · ? V · 8800T
7. An ideal step-up transformer has 950 primary turns and 5700 secondary turns. If the primary voltage is 80 V, what is the secondary voltage?
80V · 950T · ? V · 5700T
8. An ideal step-up transformer has 450 primary turns and 1350 secondary turns. If the primary voltage is 150 V, what is the secondary voltage?
150V · 450T · ? V · 1350T
9. An ideal step-up transformer has 700 primary turns and 2800 secondary turns. If the primary voltage is 90 V, what is the secondary voltage?
90V · 700T · ? V · 2800T
10. An ideal step-up transformer has 1350 primary turns and 4050 secondary turns. If the primary voltage is 130 V, what is the secondary voltage?
130V · 1350T · ? V · 4050T
11. An ideal step-up transformer has 1000 primary turns and 5000 secondary turns. If the primary voltage is 80 V, what is the secondary voltage?
80V · 1000T · ? V · 5000T
12. An ideal step-up transformer has 250 primary turns and 2000 secondary turns. If the primary voltage is 40 V, what is the secondary voltage?
40V · 250T · ? V · 2000T

12 questions · Seed 47 · 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 150 primary turns and 750 secondary turns. If the primary voltage is 40 V, what is the secondary voltage?
200 V
Vs = Vp × (Ns ÷ Np) = 40 × (750 ÷ 150) = 200 V.
2. An ideal step-up transformer has 1500 primary turns and 7500 secondary turns. If the primary voltage is 160 V, what is the secondary voltage?
800 V
Vs = Vp × (Ns ÷ Np) = 160 × (7500 ÷ 1500) = 800 V.
3. An ideal step-up transformer has 1400 primary turns and 7000 secondary turns. If the primary voltage is 140 V, what is the secondary voltage?
700 V
Vs = Vp × (Ns ÷ Np) = 140 × (7000 ÷ 1400) = 700 V.
4. An ideal step-up transformer has 1200 primary turns and 9600 secondary turns. If the primary voltage is 170 V, what is the secondary voltage?
1360 V
Vs = Vp × (Ns ÷ Np) = 170 × (9600 ÷ 1200) = 1360 V.
5. An ideal step-up transformer has 1050 primary turns and 7350 secondary turns. If the primary voltage is 20 V, what is the secondary voltage?
140 V
Vs = Vp × (Ns ÷ Np) = 20 × (7350 ÷ 1050) = 140 V.
6. An ideal step-up transformer has 1100 primary turns and 8800 secondary turns. If the primary voltage is 50 V, what is the secondary voltage?
400 V
Vs = Vp × (Ns ÷ Np) = 50 × (8800 ÷ 1100) = 400 V.
7. An ideal step-up transformer has 950 primary turns and 5700 secondary turns. If the primary voltage is 80 V, what is the secondary voltage?
480 V
Vs = Vp × (Ns ÷ Np) = 80 × (5700 ÷ 950) = 480 V.
8. An ideal step-up transformer has 450 primary turns and 1350 secondary turns. If the primary voltage is 150 V, what is the secondary voltage?
450 V
Vs = Vp × (Ns ÷ Np) = 150 × (1350 ÷ 450) = 450 V.
9. An ideal step-up transformer has 700 primary turns and 2800 secondary turns. If the primary voltage is 90 V, what is the secondary voltage?
360 V
Vs = Vp × (Ns ÷ Np) = 90 × (2800 ÷ 700) = 360 V.
10. An ideal step-up transformer has 1350 primary turns and 4050 secondary turns. If the primary voltage is 130 V, what is the secondary voltage?
390 V
Vs = Vp × (Ns ÷ Np) = 130 × (4050 ÷ 1350) = 390 V.
11. An ideal step-up transformer has 1000 primary turns and 5000 secondary turns. If the primary voltage is 80 V, what is the secondary voltage?
400 V
Vs = Vp × (Ns ÷ Np) = 80 × (5000 ÷ 1000) = 400 V.
12. An ideal step-up transformer has 250 primary turns and 2000 secondary turns. If the primary voltage is 40 V, what is the secondary voltage?
320 V
Vs = Vp × (Ns ÷ Np) = 40 × (2000 ÷ 250) = 320 V.

12 questions · Seed 47 · 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 150 primary turns and 750 secondary turns. If the primary voltage is 40 V, what is the secondary voltage?
40V · 150T · ? V · 750T
2. An ideal step-up transformer has 1500 primary turns and 7500 secondary turns. If the primary voltage is 160 V, what is the secondary voltage?
160V · 1500T · ? V · 7500T
3. An ideal step-up transformer has 1400 primary turns and 7000 secondary turns. If the primary voltage is 140 V, what is the secondary voltage?
140V · 1400T · ? V · 7000T
4. An ideal step-up transformer has 1200 primary turns and 9600 secondary turns. If the primary voltage is 170 V, what is the secondary voltage?
170V · 1200T · ? V · 9600T
5. An ideal step-up transformer has 1050 primary turns and 7350 secondary turns. If the primary voltage is 20 V, what is the secondary voltage?
20V · 1050T · ? V · 7350T
6. An ideal step-up transformer has 1100 primary turns and 8800 secondary turns. If the primary voltage is 50 V, what is the secondary voltage?
50V · 1100T · ? V · 8800T
7. An ideal step-up transformer has 950 primary turns and 5700 secondary turns. If the primary voltage is 80 V, what is the secondary voltage?
80V · 950T · ? V · 5700T
8. An ideal step-up transformer has 450 primary turns and 1350 secondary turns. If the primary voltage is 150 V, what is the secondary voltage?
150V · 450T · ? V · 1350T
9. An ideal step-up transformer has 700 primary turns and 2800 secondary turns. If the primary voltage is 90 V, what is the secondary voltage?
90V · 700T · ? V · 2800T
10. An ideal step-up transformer has 1350 primary turns and 4050 secondary turns. If the primary voltage is 130 V, what is the secondary voltage?
130V · 1350T · ? V · 4050T
11. An ideal step-up transformer has 1000 primary turns and 5000 secondary turns. If the primary voltage is 80 V, what is the secondary voltage?
80V · 1000T · ? V · 5000T
12. An ideal step-up transformer has 250 primary turns and 2000 secondary turns. If the primary voltage is 40 V, what is the secondary voltage?
40V · 250T · ? V · 2000T

12 questions · Seed 47 · 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 150 primary turns and 750 secondary turns. If the primary voltage is 40 V, what is the secondary voltage?
200 V
Vs = Vp × (Ns ÷ Np) = 40 × (750 ÷ 150) = 200 V.
2. An ideal step-up transformer has 1500 primary turns and 7500 secondary turns. If the primary voltage is 160 V, what is the secondary voltage?
800 V
Vs = Vp × (Ns ÷ Np) = 160 × (7500 ÷ 1500) = 800 V.
3. An ideal step-up transformer has 1400 primary turns and 7000 secondary turns. If the primary voltage is 140 V, what is the secondary voltage?
700 V
Vs = Vp × (Ns ÷ Np) = 140 × (7000 ÷ 1400) = 700 V.
4. An ideal step-up transformer has 1200 primary turns and 9600 secondary turns. If the primary voltage is 170 V, what is the secondary voltage?
1360 V
Vs = Vp × (Ns ÷ Np) = 170 × (9600 ÷ 1200) = 1360 V.
5. An ideal step-up transformer has 1050 primary turns and 7350 secondary turns. If the primary voltage is 20 V, what is the secondary voltage?
140 V
Vs = Vp × (Ns ÷ Np) = 20 × (7350 ÷ 1050) = 140 V.
6. An ideal step-up transformer has 1100 primary turns and 8800 secondary turns. If the primary voltage is 50 V, what is the secondary voltage?
400 V
Vs = Vp × (Ns ÷ Np) = 50 × (8800 ÷ 1100) = 400 V.
7. An ideal step-up transformer has 950 primary turns and 5700 secondary turns. If the primary voltage is 80 V, what is the secondary voltage?
480 V
Vs = Vp × (Ns ÷ Np) = 80 × (5700 ÷ 950) = 480 V.
8. An ideal step-up transformer has 450 primary turns and 1350 secondary turns. If the primary voltage is 150 V, what is the secondary voltage?
450 V
Vs = Vp × (Ns ÷ Np) = 150 × (1350 ÷ 450) = 450 V.
9. An ideal step-up transformer has 700 primary turns and 2800 secondary turns. If the primary voltage is 90 V, what is the secondary voltage?
360 V
Vs = Vp × (Ns ÷ Np) = 90 × (2800 ÷ 700) = 360 V.
10. An ideal step-up transformer has 1350 primary turns and 4050 secondary turns. If the primary voltage is 130 V, what is the secondary voltage?
390 V
Vs = Vp × (Ns ÷ Np) = 130 × (4050 ÷ 1350) = 390 V.
11. An ideal step-up transformer has 1000 primary turns and 5000 secondary turns. If the primary voltage is 80 V, what is the secondary voltage?
400 V
Vs = Vp × (Ns ÷ Np) = 80 × (5000 ÷ 1000) = 400 V.
12. An ideal step-up transformer has 250 primary turns and 2000 secondary turns. If the primary voltage is 40 V, what is the secondary voltage?
320 V
Vs = Vp × (Ns ÷ Np) = 40 × (2000 ÷ 250) = 320 V.

12 questions · Seed 47 · Age guidance, not curriculum certification