Can I use the transformer with part no
750811330
for stepdown in power supply board instead of using general purpose transformer

 

If you mean this one:

https://www.digikey.com/en/products/detail/w-rth-elektronik/750811330/2650426?utm_adgroup=Battery Products&utm_source=google&utm_medium=cpc&utm_campaign=Dynamic Search_EN_Product&utm_term=&utm_content=Battery Products&gclid=Cj0KCQjwk7ugBhDIARIsAGuvgPbN6AcMAQ48s2siObzeSahFkCL-v9A8JnAioEzEf0hnDZT0vUC998YaAo8HEALw_wcB

It is a flyback transformer designed to work at 200KHz.

DO NOT try to use this for line voltage at 50 or 60Hz.

 

That is intended as a flyback transformer not a suitable candidate for mains use.

 

If you mean this one:

https://www.digikey.com/en/products/detail/w-rth-elektronik/750811330/2650426?utm_adgroup=Battery Products&utm_source=google&utm_medium=cpc&utm_campaign=Dynamic Search_EN_Product&utm_term=&utm_content=Battery Products&gclid=Cj0KCQjwk7ugBhDIARIsAGuvgPbN6AcMAQ48s2siObzeSahFkCL-v9A8JnAioEzEf0hnDZT0vUC998YaAo8HEALw_wcB

It is a flyback transformer designed to work at 200KHz.

DO NOT try to use this for line voltage at 50 or 60Hz.

Thank you, got it

 

Connecting mains voltage to that transformer will have it act as fast acting fuse.

 

It is a flyback transformer designed to work at 200KHz.

DO NOT try to use this for line voltage at 50 or 60Hz.

If you mean this one:


It is a flyback transformer designed to work at 200KHz.

DO NOT try to use this for line voltage at 50 or 60Hz.

It is a flyback transformer designed to work at 200KHz.

DO NOT try to use this for line voltage at 50 or 60Hz.
[/QUOTE]

If you mean this one:

https://www.digikey.com/en/products/detail/w-rth-elektronik/750811330/2650426?utm_adgroup=Battery Products&utm_source=google&utm_medium=cpc&utm_campaign=Dynamic Search_EN_Product&utm_term=&utm_content=Battery Products&gclid=Cj0KCQjwk7ugBhDIARIsAGuvgPbN6AcMAQ48s2siObzeSahFkCL-v9A8JnAioEzEf0hnDZT0vUC998YaAo8HEALw_wcB

It is a flyback transformer designed to work at 200KHz.

DO NOT try to use this for line voltage at 50 or 60Hz.

can you Suggest me a transformer part number for power supply adaptor for 12v-5A

 

https://www.digikey.com/en/products/detail/triad-magnetics/FD8-12/4878694

What are the Specifications that are required for your new Power-Supply ?
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https://www.digikey.com/en/products/detail/triad-magnetics/FD8-12/4878694

What are the Specifications that are required for your new Power-Supply ?
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The Spec is 15V and 5A ...I have searched many transformers but all those are huge in size.Is it available minimum size?

 

75va sized transformers are all going to be around the same physical size, Mouser has a selection by Hammond, although 16v, how critical is it, you may have to find one that is close and remove a few turns.
The alternative to go smaller is maybe a SMPS, but even this will not be 'miniature'.
What is the application?

 

The Spec is 15V and 5A ...I have searched many transformers but all those are huge in size.Is it available minimum size?

Do you want a DC voltage of 15V rated for 5A?

 

.I have searched many transformers but all those are huge in size.Is it available minimum size?

No.
The size of a transformer is basically inversely proportional to the frequency for a given power, so the transformers that operate on the mains frequency all have about the same size for the same power rating.
Switching power supplies reduce the size of the magnetics by going to a higher frequency (typically above 20kHz).

 

Are you converting to DC? If so what is the application?
, If DC, what is the DC level voltage required?

 

The Spec is 15V and 5A ...I have searched many transformers but all those are huge in size.Is it available minimum size?

That is why no one builds mains transformer power supplies any more. For less money than the transformer, you can buy a good commercial switching supply.

For example

 

That is why no one builds mains transformer power supplies any more. For less money than the transformer, you can buy a good commercial switching supply.

I never use SMPS if I can help it.
Linears are much more rugged, also most of the stepper drive and servo amp manuf. do not recommend them for thier applications.
I pay a little extra, but get the durability,
Also if you use them for customers, they are happier if they have less break-downs !

 

That is why no one builds mains transformer power supplies any more. For less money than the transformer, you can buy a good commercial switching supply.

The market size for low voltage supplies is now so large that the prices for SMPS are incredibly low. See https://www.amazon.co.uk/DSLRKIT-75Watt-Supply-Adapter-100-240V/dp/B01LPKWLNM as an example of a nicely cased 15VDC 5A supply which works from 100 to 240 VAC. The good thing about an external supply is that it can easily be replaced if for some reason it fails, and the equipment itself is only subject to low voltage rules.

 

Try this SMPS for size ...........
https://www.digikey.com/en/products/detail/mean-well-usa-inc/IRM-90-12/11562725

3.5" X 2" X 1"
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The application is 12V-5A 60W power supply for led lights.I am going to design it tranditioal way like Stepdown Transformer>Rectification>smoothing>regulation>load. I want stepdown in firststage itself.But I think in smps it is not possible.Is it possible?

 

The application is 12V-5A 60W power supply for led lights.I am going to design it tranditioal way like Stepdown Transformer>Rectification>smoothing>regulation>load. I want stepdown in firststage itself.But I think in smps it is not possible.Is it possible?

For LED's you don't necessarily require smoothing and/or regulation.

 

Forget about the "Exact-Voltage".
You need a "Current-Regulator", preferably a "Switch-Mode" Current-Regulator,
then let the Voltage fall where it may, ( as long as it's not too crazy out of hand ).

This Circuit can handle as much as ~60-Peak-Volts,
and can easily be adjusted to any Current-Level You desire ..........
A simple AC to DC Converter,
which is capable of supplying "more than enough" Voltage and Current,
will work just fine.
You will need to consult the Spec-Sheet for your LEDs to determine the ideal amount of Current.
High-Power LEDs, ( more than approximately ~50mA ), will need a Heat-Sink.

What is the part-number of your LEDs ?, or please supply the Spec-Sheet-PDF File.
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For LED's you don't necessarily require smoothing and/or regulation.

What is the part-number of your LEDs ?, or please supply the Spec-Sheet-PDF File.

LED's can be "overdriven" with a PWM signal as long as the average power doesn't lead to thermal runaway. It would be good to know the specification of the LEDs you plan to use and the quantity. Assuming you have adequate heat sinks, it might be helpful to raise your secondary voltage to 24V AC putting more LEDs in series in a serial/parallel set up. You could then use a 555 astable to adjust the brightness by changing the mark/space ratio with a potentiometer and turning on the series strings with MOSFETS. Whilst you should dump some power with a resistor in series with each string, switching the strings on and off quickly is the most efficient way to control brightness. The 555 frequency needs to be significantly larger than mains frequency to avoid visible changes in brightness.