How to convert dc voltage into higher dc voltage using transformer?

In summary, the conversation was about how to convert a 9V DC voltage into 120V DC using a transformer. The solution was suggested to use a boost converter to step up the voltage, but the issue was how to convert the input DC into AC. The conversation also touched on the power requirements and the need to know either the current or power of both the 9V source and the 120V source. The conversation also mentioned a possible solution using an isolated Flyback converter, but the discussion ended with the reminder to prioritize safety and knowledge before working with high voltage circuits. Some resources were also shared for further information and learning.
  • #1
tefavolc
29
0
how to convert dc voltage into higher dc voltage using transformer?

i am tring to convert 9 volt dc into 120 volt dc , and i ve to use transformer ,,, the problem is the transformer must have input ac voltage as it work on flux variation . i think the solution is to convert the input dc into ac and then use bridge rectifer at the output to convert it agine into dc ,, but how can i convert the input dc into ac ??
 
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  • #3
  • #4


n.karthick said:
You can use boost converter to step up DC. Basic information can be found in wikipedia page
http://en.wikipedia.org/wiki/Boost_converter
is there an electronic devise for the boost converter ,,, or i ve to construct the circuit my self??
 
  • #5


What power requirement do you need?

What power is available with 9v source?
 
  • #6


Quantum-lept said:
What power requirement do you need?

What power is available with 9v source?

sry ,,but how can i know that ??
 
  • #7


Quantum-lept said:
What power requirement do you need?

What power is available with 9v source?

tefavolc said:
sry ,,but how can i know that ??

Another way of asking the question: what are you using for a 9V source? What will be connected to the 120V source?

Also, you'll need to know either the current or the power for both the 9V source and whatever is connected to the 120V source. These should be specified somewhere.

The more information you can provide about your project, the more likely you are to get useful advice.
 
  • #9


A transformer works on the principle that the magnetic field is induced by the derivative of the flux. Basically, you need the alternating voltage for the device to work while dc voltage does not do this.
 
  • #10


i ve reached a devise that convert the dc into ac ,,it depend on the unstable of transistor as beta changes so ic and ib changes making flux variation in the transformer coils(12v\220v) and produce ac voltage in the other terminal,,,, but the problem is when i measure Vout with R1=infinty it give value of 150 volt and when i change the value of R1 the voltage change with it directly .. how can i make the voltage constant what ever resistance i put?
shokrn mokdamn (thnx in advance) :D
 

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  • #11


tefavolc said:
.. how can i make the voltage constant what ever resistance i put?
You can't.

If you think you can, you shouldn't be working on 120V circuits. Instead, learn about electronics with lower voltage circuits first. It's a simple matter of your own safety.
 
  • #12


Redbelly98 said:
You can't.
why??!would u please explain
 
  • #13


Using an isolated Flyback converter (or two) you could satisfy the constraints of "increasing a dc voltage by 'using' a transformer".
 
  • #14


.. how can i make the voltage constant what ever resistance i put?


You'll have to increase the power capability of your DC source on the primary so that it can handle the load on the secondary.

Power is finite in this circuit. Let's say that your DC source can supply 100mW of power, and for simplicity, we'll assume a lossless transformer

P = V * I -> P/V = I

0.1 / 150 = 667 uA

So if your DC source can supply 100mW of power, the most current you could draw on your secondary would be 667 micro-amps to sustain 150V

V = I * R -> R = V/I

150 / 667^-6 = 224887 ~ 224k

So your biggest load would have to be equal to or greater than 224k. If you increased the load beyond that (lowered the resistance so that current increased), your voltage level would drop. For example, assume a 100k load.

150 / 100k = 1.5 mA

P = V * I -> V = P/I

In this example, we have said the max power your source can supply is 100 mA, so:

V = 0.1 / 1.5^-3 = 66.7V

As you can see, you have exceeded the max power of your source, and your voltage levels took a hit and fell from 150V to 66V.

To make this simpler, check your load and see how much power it consumes. If you're plugging in a TV or a space heater, see how many Watts it consumes and then make sure your DC source on the primary can supply that many Watts.
 
  • #15


tefavolc said:
how can i make the voltage constant what ever resistance i put?
shokrn mokdamn (thnx in advance) :D
Redbelly98 said:
You can't.
tefavolc said:
why??!would u please explain
Every voltage supply has a maximum output current. If you choose R small enough so that Vout/R is larger than that maximum current, the output voltage must drop to a lower value.

Since I have answered your question, could you return the courtesy and answer mine?
Redbelly98 said:
what are you using for a 9V source? What will be connected to the 120V source?
 
  • #16


Redbelly98 said:
Every voltage supply has a maximum output current. If you choose R small enough so that Vout/R is larger than that maximum current, the output voltage must drop to a lower value.

Since I have answered your question, could you return the courtesy and answer mine?
im using for 9 volt source an (9volt battry panasonic)...i will not connect spceific thing just test the output on variable resistance to see the output power,, i just want to built that devise for knowlage and experince ,, and later i can connect it to some devise which need high input voltage..

thnx for you all for helping me :)) :))
 
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  • #17

Can a Transformer Be Used to Increase DC Voltage?

No, a traditional transformer, which is designed for alternating current (AC), cannot be used to directly increase the voltage of a direct current (DC) source. Transformers rely on the changing magnetic fields produced by AC to induce voltage changes in the secondary coil. In DC circuits, where the voltage remains constant, the transformer does not operate as intended.

What Alternatives Are Available for Increasing DC Voltage?

There are several methods available for increasing DC voltage:

1. Voltage Multiplier Circuits:

Voltage multiplier circuits, such as Cockcroft-Walton voltage multipliers, can be used to step up DC voltage. These circuits use diodes and capacitors to accumulate charge and produce a higher DC voltage at the output.

2. Boost Converters:

Boost converters, also known as step-up converters, are electronic devices that can increase DC voltage levels efficiently. They operate by storing energy in an inductor and then releasing it to produce a higher output voltage.

3. Charge Pumps:

Charge pumps are electronic circuits that can generate a higher DC voltage from a lower DC voltage by using switches and capacitors to transfer and accumulate charge.

4. Voltage Regulators with Step-Up Functionality:

Some voltage regulators have built-in step-up functionality, allowing them to provide a higher output voltage than the input voltage. These regulators are often used in power supply applications.

What Are the Limitations of DC Voltage Conversion Methods?

While there are methods available to increase DC voltage, it's essential to be aware of their limitations:

1. Efficiency:

Not all methods are equally efficient, and some may result in power losses during the conversion process.

2. Voltage Range:

The ability to increase voltage may be limited by the components and circuitry used. Extreme voltage boosting may require specialized components.

3. Complexity:

Some methods, such as voltage multiplier circuits, can be complex to design and implement, depending on the desired output voltage level.

What Applications Require DC Voltage Conversion?

DC voltage conversion is necessary in various applications, including:

1. Power Supplies:

Power supplies often require the conversion of lower DC voltages to higher ones for electronic devices and equipment.

2. Renewable Energy Systems:

Renewable energy systems, such as solar panels and wind turbines, may require voltage conversion to match the energy output with the requirements of the electrical grid or storage systems.

3. Battery-Powered Devices:

Battery-powered devices may use boost converters to maintain a stable output voltage as the battery voltage decreases.

4. Electric Vehicles:

Electric vehicles employ voltage conversion to efficiently use the battery's stored energy to power the vehicle's motor.

Can Transformers Still Play a Role in DC Systems?

While traditional transformers are not suitable for directly increasing DC voltage, they can still be used in DC systems for purposes such as isolation, impedance matching, and current transformation. However, for voltage increase in DC applications, other methods like those mentioned earlier are more appropriate.

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