some circuits contains 2 transformers. one before bridge and one after bridge. What is the purpose of using 2 transformer in a circuit?

 

It would help answer your question if we could see a schematic or other illustration of what you are thinking of.

 

It would help answer your question if we could see a schematic or other illustration of what you are thinking of.

It is PFC stage of RDR382 of led driver.

 

Perhaps one is for PFC and the other is for regulation.

 

I do not see any transformer before the bridge. All I see is common mode EMI filter.
http://led-driver.power.com/sites/default/files/PDFFiles/rdr382.pdf
And after the bridge we have a PFC inductor.

 

http://led-driver.power.com/design-...r-382-150-w-power-factor-corrected-llc-power/

Thank you!

 

I still do not see any transformer transformer before the bridge.

 

L1 is a common mode choke, and is usually not thought of as a transformer. It serves two purposes, both related to conducted electromagnetic interference. The most important part is that it makes sure that the same amount of high frequency AC current that goes through the line goes through neutral. It also provides inductance between the power line and the rest of the power supply. Working with C1, it reduces the amount of high frequency noise gets from the power supply to the power line.

Now I have to close this thread because I just realized that the power supply is not isolated.

The owners of All About Circuits has elected not to host discussions of automotive electrical system modifications/enhancements due to safety concerns, the potential of legal ramifications and the possible circumvention of vehicle regulations at the state and federal level.

This thread is against the AAC forum rules, Chapter 6, as seen here:

6. Restricted topics. The following topics are regularly raised however are considered “off-topic” at all times and will results in Your thread being closed without question:

• Any kind of over-unity devices and systems
• Automotive modifications
• Devices designed to electrocute or shock another person
• LEDs to mains
• Phone jammers
• Rail guns and high-energy projectile devices
• Transformer-less power supplies

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Automotive modifications of any kind are strictly forbidden. Therefore, this thread will be closed.

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You might find answers to your questions in one of these forums:

http://forum.allaboutcircuits.com/showthread.php?t=54400

Another good forum that shares many of the same membership is http://www.electro-tech-online.com/ . Good

 

Hey, what about the output transformer? From what I see output transformer provide galvanic isolation.

 

I think T1 is output transformer.
Thank you!