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 ?..
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 ?..
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:
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 ?..
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 ?..
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.
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
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.
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.
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.