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A transformer has 600 turns in the primary coil and 100 turns in the secondary. If 120 V AC is applied to the primary, what is the output voltage?
Vp/Vs=Np/Ns⇒120/Vs=600/100=6⇒Vs=120/6=20 V
A step-down transformer is used to reduce a 220 V supply to 22 V. If the primary has 440 turns, how many turns does the secondary need?
220/22=440/Ns⇒10=440/Ns⇒Ns=440/10=44 turns
A step-up transformer increases voltage from 100 V to 500 V. If the primary has 50 turns, how many turns must the secondary have?
Vp/Vs=Np/Ns⇒100/500=50/Ns⇒Ns=500×50/100=250 turns
A transformer has a primary voltage of 60 V and a turns ratio of 3:1 (primary:secondary). What is the voltage across the secondary coil?
Vp/Vs= 1/3-> Vs=60/3=20V
A transformer has a turns ratio of 5:1 (primary:secondary). If the current in the primary is 1.0 A, what is the current in the secondary?
Ip/Is=Np/Ns=1/5⇒Is=1.0×5=5.0 A
A 90 V AC source powers the primary of a transformer with 300 turns. The secondary has 100 turns. What is the current in the secondary if the load draws 2.0 A from the primary?
IP/IS=NS/NP=100/300=1/3⇒Is=2/(1/3) = 6 A
A 240 V AC source is connected to a transformer’s primary with 800 turns. If the secondary has 400 turns, what is the output voltage?
240/Vs=800/400=2⇒Vs=240/2=120 V
A transformer with a turns ratio of 2:1 is connected to a 1.5 kΩ resistor in the secondary. If 100 V is applied to the primary, how much power is dissipated in the resistor?
find Vs: Vs= 50 v
find power: P=V2 / R = 1.6 W
A transformer with 300 turns in the primary and 150 turns in the secondary provides 6.0 A to a load. What is the current drawn from the source?
Ip/600=150/300=0.5⇒Ip=6.0×0.5=3.0 A
A transformer’s secondary provides 10 A at 12 V. If the turns ratio is 10:1 (primary:secondary), what is the current in the primary? (give me solutions)
Ip=1.0 A