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In DC, flow of current is controlled by resistance only where as in AC it is done by Impedance which is combination of Resistance , inductive and capacitive reactances.
Reasons:
- In Transformers resistance of the transformer's core windings are very low due to which if you will connect transformer across DC supply then it will draw a heavy current which will burn out is winding and it may damage the equipment too.
- Transformers works of the principal of Induction (Mutual/Self) that is possible in AC only because in DC there is no induction therefore even if transformer's windings anyhow withstand with DC there will be no voltage output at output terminals of the transformer, therefore it is useless to connect transformer on DC supply.
Wiki User
∙ 12y ago
Wiki User
∙ 10y agoA transformer needs an alternating current supply because trying to apply dc to it would just result in excessive current, a blown fuse if you are lucky and no output voltage.
Wiki User
∙ 15y agoThere are no alterations of current (AC) to induce current to flow in the secondary winding of the transformer.
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Can a constant dc current induce a steady state voltage in a transformer?
No. A constant DC current of sufficient magnitude induces smoke in a transformer.
Why does a transformer only work for AC supply and not DC supply?
A transformer makes and collapses a magnetic Field inside 60 times a second for home power in North America, 50 times a second in Europe. The building and collapsing of a magnetic field "Induces" a voltage in another transformer winding. DC current only creates a stable magnetic field and this will not create or induce voltage in the other winding. Normally covered in grade 5 science where I live.
Why ac current is used in a transformer?
AC current or DC current can be used in transformers. A transformer is made of two coils of wire, the input coil induces a current into the output coil. Transformers change the voltage either up (step up transformer) or down (step down transformer). The amount of change in voltage is dependent solely on the number of windings in both coils in the transformer. DC transformers work exactly the same way AC transformers do.
When dc voltage is supplied to the primary coil of the transformer then the voltage be induced in secondary or not?
The windings of a transformer have both resistance and inductance. When you apply an AC voltage to the primary winding, the opposition to current flow is a combination of resistance and inductive reactance; although the resistance of the winding is relatively low, its inductive reactance is high. The resulting impedance (the vector sum of resistance and inductive reactance) will, therefore, be high and the resulting current will be low.If, on the other hand, you applied a DC voltage to the winding, the only opposition will be the low resistance of the winding. So, if the value of DC voltage is roughly the same as the rated AC voltage, a large value of current would result -high enough to probably burn out the winding.Since transformers work on the principle of mutual induction, a fluctuating magnetic field is necessary to induce a voltage into the secondary winding. Since a fluctuating magnetic field requires a fluctuating current, a transformer will only work if an AC voltage is applied to its primary winding.So, not only will a transformer not work when a DC voltage is applied to its primary winding, it will probably burn out the primary winding.
What is the difference between a battery charger and a transformer rectifier?
A battery charger is a DC voltage source followed by some kind of regulator that controls the current flowing into the battery. Depending on the type of battery, this regulator might be simple, based on current and/or voltage, or it might be complex, based on voltage slope. A transformer rectifier is simply one of the part of the DC voltage source.
Does electrical transformer use a DC or AC source?
A transformer is a device to convert high voltage AC to low voltage AC & vice-versa. It works on the principle of induction. Since induction occurs only in an AC supply, a transformer cannot work on DC.. So, it is not possible to convert DC supply to AC using transformer. You would need an inverter to convert DC to AC.
How does a DC transformer work?
transformer cannot be worked on DC because as the dc is constant there will be no change of flux & may lead to shot circuit.
Can dc current work on transformer?
Transformer is by definition can transform only AC current. But it's possible to build device that can step up or step down DC voltage directly. These are called DC-DC converters not transformers.
Why we used ac volt in supply line instead of dc volt?
AC voltage is more sufficient than DC voltage. Moreover, an AC transformer can be developed but DC voltage will make it harder. Without a transformer, we cannot turn the high and low voltaged into each-other.
How do you make ac into DC in a ac transformer?
You can not change AC into DC using a transformer. A transformer changes the voltage levels. To change AC into DC, you would need a rectifier. To change that into smooth DC you need a capaciter and a voltage regulater
Why doesn't transformer work on a DC supply?
to have transformer action there should be an alternating magnetic flux.but dc supply cannot produce alternating flux.
Can a constant dc current can induce a steady state voltage in a transformer?
No, the current has to change for a voltage to be induced in the transformer.
In D.C supply the transformer is not connected why?
In a DC power supply a transformer is connected. The only time there would be no transformer used would be if the DC voltage wanted was 120 VDC. The transformer in the power supply is connected to 120 VAC on the primary side and the secondary side of the transformer is connected to either a half wave or a full wave diode bridge. The voltage out of the diode bridge will be the same output voltage potential as the transformer's secondary voltage but it will be a DC (Direct Current) potential.Reading the question in another way, transformers are not connected in a DC circuit. The reason being is that the transformer operates on a collapsing magnetic field. This field induces a voltage into the secondary side of the transformer. Since the DC circuit does not operate on the principle of a collapsing field except when the circuit is opened, the transformer would not operate as a transformer should..
If a dc voltage of 12v is added to the secondary of step down transformer and rating of transformer is 220 input and 12v output what will be the result from primary of transformer?
A DC voltage added to one side of a transformer has no effect on the other side.
Device used to step voltage up or down?
As transformers do not work with DC., the answer is a voltage divider network (step down) or a voltage multiplier network (step up).
Why do you obtain more dc voltage than ac voltage in power supply design by using transformer?
You don't. Transformers only work with AC voltage. Their input will be an AC waveform, and their output will be an AC waveform. Other electronics are used to convert the stepped down AC waveform from the transformer to DC.
Can a constant dc current induce a steady state voltage in a transformer?
No. A constant DC current of sufficient magnitude induces smoke in a transformer.
