difference between 110v transformer and 220v transformer

[dinesh401]

The chargers like our mobile and laptop chargers normally take 220v input and it works fine.
But whereas in some trains they give a supply voltage of 110v. If we connect to the supply voltage and if we use it then also its works fine.

But my doubt is, We are having a 220v to 12v step down transformer present in the charger. But now we are reducing the primary voltage to 110v ac. If there any effect when decreasing to 110v ac ?..

thankyou....

 

[tpetar]

The chargers like our mobile and laptop chargers normally take 220v input and it works fine.
But whereas in some trains they give a supply voltage of 110v. If we connect to the supply voltage and if we use it then also its works fine.

But my doubt is, We are having a 220v to 12v step down transformer present in the charger. But now we are reducing the primary voltage to 110v ac. If there any effect when decreasing to 110v ac ?..

thankyou....

Is there some point of this, if you use transformer 220V to 12V at 110V on primary coil voltage on secundar will be 6V! Do you need 6V or 12V on secundar.

Some motors can be overheated if they work on 110V because lowered RPM and lowered cooling, also power is not the same, and can be some problem on higher load, even winding burnouts. :wink:

 

[jeffrey samuel]

there is a small error there is no step down transformer in the battery charger

for li ion type check this out


@tpetar we need 12 V for cell phone charging right he means 12 V in the op

 

[tpetar]

We are having a 220v to 12v step down transformer present in the charger. But now we are reducing the primary voltage to 110v ac. If there any effect when decreasing to 110v ac ?..

On secundar you will get lower voltage, and problem with charging of battery.

I think he meant on trafo, gretz, cap... then charging controller represented by some IC,...

 

[FvM]

You should check the charger first. Most have wide range input 90-240 VAC or similar.

 

[godfreyl]

A lot of devices work fine with 115V or 230V. They use a voltage-sensing circuit to switch the rectification scheme as needed.

edit: Oops, cross-post with FVM.

Most have wide range input 90-240 VAC or similar.

Yes, those ones.

 

[jeffrey samuel]

can anyone be kind enough to tell how this variable response is provided in those chargers

i checked and found the rating as 90V- 250V ac ip and 12 V op how is it possible

 

[tpetar]

But my doubt is, We are having a 220v to 12v step down transformer present in the charger. But now we are reducing the primary voltage to 110v ac. If there any effect when decreasing to 110v ac ?..

We speak about transformer (50Hz/60Hz) based power supply or switchers power supply such as laptop psu ?

 

[jeffrey samuel]

We speak about transformer (50Hz/60Hz) based power supply or switchers power supply such as laptop psu ?

i think he has difficulty in identifying it he is talking about laptop supply

 

[FvM]

We speak about transformer (50Hz/60Hz) based power supply or switchers power supply such as laptop psu ?

As you like.

The original post is speaking of transformers but asking about mobile phone and mobile computer power supply. Mobile computer are exclusively using switched mode supply, mobile phones mostly.

For small swichted mode power supply (SMPS) wide range input voltage is the regular case. It's easily achieved with flyback topology.

 

[jeffrey samuel]

awesome thanks again fvm these tiny things manage so wide range of voltage and yet how is their response constant are they not using transformers inside of them then

 

[godfreyl]

can anyone be kind enough to tell how this variable response is provided in those chargers

Most, if not all, use SMPS, which allows output voltage to be independent of input voltage to some extent.

I remember seeing one years ago that used the voltage sensing mentioned above. That used a simple bridge rectifier for 240V input, but switched to a voltage doubler circuit for 120V input.

I don't know how common that is now, but it's a technique you could use even with transformer-based supplies.

 

[jeffrey samuel]

Most, if not all, use SMPS, which allows output voltage to be independent of input voltage to some extent.

I remember seeing one years ago that used the voltage sensing mentioned above. That used a simple bridge rectifier for 240V input, but switched to a voltage doubler circuit for 120V input.

I don't know how common that is now, but it's a technique you could use even with transformer-based supplies.

so you mean that there is a limiter voltage once reached the ckt turns into a doubler ckt then feeds the voltage into the transformer

but how does it work any schematics of it

pls help planning to implement in project

 

[godfreyl]

so you mean that there is a limiter voltage once reached the ckt turns into a doubler ckt then feeds the voltage into the transformer

No, the doubler or bridge comes after the transformer. They both convert AC to DC.

It has to switch between:

• 240V AC => transformer => 20V AC => bridge rectifier => about 25V DC
• 120V AC => transformer => 10V AC => voltage doubler => about 25V DC

That's not a very efficient use of the transformer, though. It would be better to use a transformer with two primaries and connect them either in series or parallel.

The voltage sensing arrangement may be worthwhile with SMPS. Then it has to switch between:

• 240V AC => bridge rectifier => 330V DC => SMPS
• 120V AC => voltage doubler => 330V DC => SMPS

...and the SMPS doesn't have to cope with such a wide range of input voltage.