cores

[maylar]

Originally posted by CeramicMan
For a car amp you say... What about building a boost converter? Unless I'm missing something here, the secondary windings with a fixed turns ratio ratio seem like unnecessary complications. Do the secondary windings have to be isolated for your application?
CM

Tough to get +/- voltages that way. Car audio power amps all use centertapped split supplies, just like any other amp.

[Ultima Thule]

Originally posted by Easyamp

I'm just learning, and trying to figure out the smps's. But I guess once I 'm able to properly build my own I will use it as a psu in a car audio system, when I get a car.

It's just one I found on an old APC UPS board I salvaged so I don't know much about it. I do know it's important when calculating frequency and load as well as other stuff, to know what core your using, but I'm just experimenting.

Well, I thought so!

What are you BTW trying to achieve with your soundcard test?

You do know that SMPS's use (almost) only square wave?!

I would suggest you to borrow a good SMPS cookbook from the library to get acquainted with the technology, or why not search the web first.

And when starting to make some SMPS you are (IMO) quite dependet of an oscilloscope, if you dont have an inductance meter you can naimly use the scope also for measuring the inductance in your choke etc, if you know how to do, good luck!

[sss]

i'm working on a car amp also
i'm making a power supply that consists of an H bridge that will be connected to a transformer ,i think thats the easiest way because u can do that with no scope

BTW if i will use a regular coil transformer that suppose to work at 50hz will it be ok to use it for 100hz or higher?

[Easyamp]

What are you BTW trying to achieve with your soundcard test?

I stated this in my first post, just to see the coils effeciency at different frequencies other then the calculated frequency.

You do know that SMPS's use (almost) only square wave?!

I used NCH tone generator's square wave function, knowing that most smps's use square wave.

I used my core's cross section and assumed ferite material, and an online toroid calculator to find the primary wind number for 22khz.

The core works fine, all I was curious about was the odd dmm readings.

Be carefull berfore your soundcard is broken.

I didn't notice this before, not to worry the sound card is buffered through a simple class ab amplifier and then to the coil so I could achieve more realistic messurements.

[maylar]

Originally posted by sss
i'm working on a car amp also
i'm making a power supply that consists of an H bridge that will be connected to a transformer ,i think thats the easiest way because u can do that with no scope

BTW if i will use a regular coil transformer that suppose to work at 50hz will it be ok to use it for 100hz or higher?

Iron core transformers don't like square waves.