What voltage appears across the primary coil of this transormer

In summary, by using the equation Vs/Vp = 120/6, we can determine that the voltage applied to the primary coil is 2400 V when 120 V is applied to the secondary coil in a step down transformer with a voltage ratio of 20.
  • #1
carrieunder
2
0

Homework Statement


A step down transformer produces a voltage of 6.0 V across the secondary coil when the voltage across the primary coil is 120 V. What voltage appears across the primary coil of this transormer if 120 V is applied to the secondary coil?


Homework Equations



Vp/Vs=Np/Ns=Is/Ip .... ? (not sure if that is relevant really)

The Attempt at a Solution



i know Vs/Vp = 120/6

i think i don't really know what to do with the 120 v applied to the secondary coil
i added 120 to the 6 = 126 that means 6 was multiplied by a factor of 21
so i multiplied the top value of the ratio (120) by 21 and got 2520 v
but I am really not sure if that's right at all? what does "120 V is applied" in mathematical terms?
 
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  • #2
You've got everything so right, I'm not sure how you can go wrong. Vs/Vp=120/6=20. So if Vp=6V, Vs=20*Vp=120V. Now suppose Vs=120V? Where is the 21 factor coming from? You don't add the secondary to the primary, it's just a ratio.
 
Last edited:
  • #3
ok i get it i made a stupid mistake
so its really 120 X 20 right?
so the answer is 2400 ?
 
  • #4
carrieunder said:
ok i get it i made a stupid mistake
so its really 120 X 20 right?
so the answer is 2400 ?

Yes.
 

FAQ: What voltage appears across the primary coil of this transormer

What is a transformer?

A transformer is an electrical device that is used to transfer electrical energy from one circuit to another through the process of electromagnetic induction. It consists of two or more coils of wire wrapped around a magnetic core.

What is the primary coil of a transformer?

The primary coil is the coil of wire that receives the input voltage and current from the power source. It is connected to the power source and is responsible for creating a changing magnetic field within the transformer.

What factors determine the voltage across the primary coil?

The voltage across the primary coil is determined by the number of turns in the primary coil, the input voltage from the power source, and the turns ratio of the transformer. The turns ratio is the ratio of the number of turns in the primary coil to the number of turns in the secondary coil.

How does the voltage across the primary coil affect the output voltage?

The output voltage of the transformer is directly proportional to the voltage across the primary coil. This means that if the voltage across the primary coil increases, the output voltage will also increase. However, the turns ratio of the transformer also plays a role in determining the output voltage.

Can the voltage across the primary coil be changed?

Yes, the voltage across the primary coil can be changed by adjusting the input voltage from the power source or by changing the turns ratio of the transformer. However, it is important to note that the output voltage will also be affected by these changes.

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