How does a transformer step down voltage while increasing current?

In summary, the conversation discusses the relationship between voltage and current in a transformer. The voltage is increased in a step-up transformer, but the current decreases proportionally to maintain the same power. This is because the power in equals the power out, according to the formula P=IV. In a DC transformer, the reactance of the inductor is zero and it acts as a dead short. The turns ratio in a transformer also plays a role in the relationship between voltage and current. The primary coil creates a rotating magnetic field which induces a current in the secondary coil.
  • #1
Taylor_1989
402
14
Here is my problem I am having: I am having trouble seeing how current is step down in a transformer when the voltage increase. This is how I see it. In a battery ( I know d.c just using as example. ) The voltage is basically an electric field created by the internal circuit in the battery, so the work done on the electrons to give them the energy to move from a low to a high potential is done by the battery, so a 12V energy is given to each Colombo of charge so the current would flow at X amount, but if you wanted to increase current flow you would increase the voltage so more energy is given to each Colombo of charge mean they move fast so to speak, I do realize that electrons don't move that quick, it the effect of the electric field throughout the conductor (hope I am right saying that). But when I look at a A.C transformer e.g step up the voltage has increased but the current has decreased, why is this? could someone please explain.

I do apologize if some of the information I put is incorrect, I am self taught, so I can only quote what I have read so far.
 
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  • #2
Forget about the stuff you just said...

Simple as this...power in = power out. (minus some minor losses)

P=IV

Change the voltage...the current changes proportionally to make the same power...or watts.

Also, a trasformer will not work in DC. A transformer in DC is just a dead short. Reactance of a inductor is JWL. W=0 in DC. Therefore zero resistance...dead short.

To add a little more...there is a turns ratio in the transformer. To go from 120 volts to say 12 volts...you could have 1000 windings of coil on the primary side and 100 windings of coil on the secondary side. The primary coil creates a rotating magnetic field that induces a current into the secondary side also creating a rotating magnetic field. Some of the other gurus on here will have to give the the details down to the electrons and coloumbs and so forth.
 
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Related to How does a transformer step down voltage while increasing current?

1. What is the difference between voltage and current in AC circuits?

Voltage is the measure of electrical potential difference between two points in a circuit, while current is the flow of electrical charge through a circuit. AC stands for alternating current, which means the direction of current flow changes periodically over time.

2. How are voltage and current related in AC circuits?

In an AC circuit, voltage and current are directly proportional to each other. This means that as voltage increases, current also increases, and vice versa. This relationship is described by Ohm's law: V = IR, where V is voltage, I is current, and R is resistance.

3. What is the unit of measurement for voltage and current in AC circuits?

Voltage is measured in volts (V) and current is measured in amperes (A) in AC circuits. These units are named after scientists who made significant contributions to the study of electricity.

4. How does the frequency of AC voltage affect current?

The frequency of AC voltage refers to the number of cycles per second that the direction of current flow changes. As the frequency increases, the current also increases. This is because the faster the direction of current changes, the more charge can flow through the circuit in a given amount of time.

5. What are some common applications of AC voltage and current?

AC voltage and current are used in a wide range of applications, including powering household appliances, lighting, and electronics. They are also used in power grids to distribute electricity to homes and businesses. In addition, AC voltage and current are used in medical equipment, telecommunications, and industrial machinery.

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