# Secondary voltage and current?

• SAT2400
In summary, for a step-down transformer with a turn ratio of 4:1 and 100% efficiency, the secondary voltage and current are 30V and 4A respectively, when the primary voltage and current are 120V and 1A.
SAT2400
Secondary voltage and current??

## Homework Statement

A load resistor is placed across the secondary terminals of a step-down transformer with a turn ratio of 4:1. If the primary voltage and current are 120V and 1A., What will be the secondary voltage and current? Assume 100% efficiency.

## Homework Equations

Ns/Np = Vs/Vp = Ip/Is

## The Attempt at a Solution

Ns should be 4,,right??
but If Ns = 4..then, I don't get the right answer...
why is Np 4?? Np is primary isn't it??

The answers were 30v and 4A.

SAT2400 said:
A load resistor is placed across the secondary terminals of a step-down transformer with a turn ratio of 4:1. If the primary voltage and current are 120V and 1A., What will be the secondary voltage and current? Assume 100% efficiency.

Ns should be 4,,right??
but If Ns = 4..then, I don't get the right answer...
why is Np 4?? Np is primary isn't it??

The answers were 30v and 4A.

Hi SAT2400!

It's a step-down transformer, and you're told the ratio is 4:1, so Ns/Np = 1/4.

Yes, you are correct that Ns represents the number of turns on the secondary coil and Np represents the number of turns on the primary coil. In this case, Ns is 4 times Np because the turn ratio is 4:1.

Using the equation Ns/Np = Vs/Vp = Ip/Is, we can solve for Vs and Is. We know that Ns/Np = 4, and we are given Vp and Ip. So, we can plug in these values to the equation to solve for Vs and Is.

Vs/Vp = Ip/Is
Vs/120V = 1A/Is
Vs = 120V * (1A/Is)
Vs = 120V * (1A * 4)
Vs = 120V * 4
Vs = 480V

Is = 1A * (Ns/Np)
Is = 1A * (4/1)
Is = 4A

Therefore, the secondary voltage will be 480V and the secondary current will be 4A, assuming 100% efficiency. It is important to note that in real-life situations, there may be some energy loss and the efficiency may not be 100%, resulting in slightly different values.

## What is secondary voltage and current?

Secondary voltage and current refer to the electrical energy that is produced or consumed by a secondary circuit in a transformer. In a transformer, the primary circuit is connected to a power source, while the secondary circuit is connected to the load.

## How is secondary voltage and current related to primary voltage and current?

In a transformer, the secondary voltage is directly proportional to the primary voltage, and the secondary current is inversely proportional to the primary current. This means that if the primary voltage increases, the secondary voltage will also increase, and if the primary current decreases, the secondary current will increase.

## What is the difference between secondary voltage and current in a step-up transformer?

In a step-up transformer, the secondary voltage is higher than the primary voltage, while the secondary current is lower than the primary current. This allows for voltage to be increased while current is decreased, making it suitable for long-distance power transmission.

## How does secondary voltage and current affect the efficiency of a transformer?

The efficiency of a transformer is affected by the ratio of secondary voltage to primary voltage, also known as the turns ratio. The closer the turns ratio is to 1:1, the more efficient the transformer will be. This means that the higher the secondary voltage and lower the secondary current, the more efficient the transformer will be.

## What are some factors that can affect secondary voltage and current?

Secondary voltage and current can be affected by various factors such as the type and quality of the transformer, the load connected to the secondary circuit, and the resistance of the wires used in the circuit. Temperature and frequency can also have an impact on secondary voltage and current.

Replies
4
Views
1K
Replies
5
Views
2K
Replies
3
Views
2K
Replies
2
Views
2K
Replies
2
Views
3K
Replies
7
Views
1K
Replies
1
Views
880
Replies
7
Views
1K
Replies
17
Views
4K
Replies
1
Views
3K