Why can a tranceformer not be used to step-down/up dc voltage?

Question

Please answer in class 12 level

Answer 1

A tranformer works using induction in an alternating current.

As a current passes through a conductor, it produced a magnetic field. In alternating current, the voltage follows a sine wave (normally 50 or 60 Hz depending on where you are in the world). As the voltage builds up to its peak, the current flows more strongly, then weakens until it flows back in the opposite direction. This means that the strength of the magnetic field produced by the current also follows a sine wave. In the same way that a current passing through a conductor produces a magnetic field, the opposite it also true and a conductor moving through a magnetic field has a current induced in it. In the transformer, a ferrous core has current induced in it. Although the core doesn't move, the magnetic field does which has the same effect. Have a look at the link for a detailed description end to end of how the transformer works.

To answer your question, the operation of the transformer depends on the rise and fall of the magnetic field. This is why it only works with AC. A DC current is constant voltage and current and so the associated magnetic field doesn't change once it has reached maximum.

Answer 2

A transformer works on the principle of induction.
The primary coil of the transformer induces a voltage in secondary coil propotional voltage applied to it. For this to happen there must a varying magnetic flux produced by the primary coil. Since U supply a DC voltage, magnetic flux produced by the pri coil is zero due to the fact that the frequency of a DC is zero (Note: The magnetic flux produced is directly propotinal to the applied frequency) Hence a DC voltage cannot be stepped up or down but a pulsating DC can be tried.

Answer 3

Transformers work on AC voltage. If you put DC in then it will just waste the electricity. Nothing will come out.

Transformers work by putting AC into the primary coil. This causes a changing magnetic field. The changing magnetic field is turned back into AC electricity at a different voltage by the secondary coil.

With DC the magnetic field will not change and so the output coil will not move any electrons and so not make any electricity.

Answer 4

To step up DC using capacitors, I think you first need to invert to AC, then use the capacitors. To create the spark you do not need DC. So just invert and transform to required voltage. There are many ignition transformers on the market.

Answer 5

the entire theory of a transformer relies on a-c current, in that the changing inductance field keeps crossing the windings in the step up/down transformer, the number of windings on the other side of the field determine what way the charge will go.. it then must be sent thru a rectifier bridge to attain d-c current, that field does not change in inductance its a steady field all of the time. its great if you want to creat a solid magnetic field, but not much else

Answer 6

transformer works on principle of INDUCTION,which is caused due to changing flux as the AC voltage is not of fixed magnitude but is of sinosoidal nature but DC voltage is of fix magnitude ,due to this there is no induction in case of DC voltage.

Answer 7

a transformer is based on the principle of induction which is only there when there is a change in voltages which is not possible in dc voltage

Answer 8

A transformer is transparent to a d\c voltage.
It would go to maximum current and burn out.

Answer 9

principle of transformer is based on mutual inductionand dc does not produce mutual induction.since change in flux will be zero.