Power Transformer help

[Electronics4you]

Hi There,

Making a stabilized power supply for my PIC development board lead me to a datasheet for the Tamura Power transformer PL10-10-130B:

**broken link removed**

In the table for output voltage there is a strange description for the series connection. It says 10.0CT (Centertap). Does that mean, that I get 5V from both outputs, if I use one of the pins as output and ground the centertap? Why is it described like so and not by 2x5.0V?

The parallel connection gives 5V~@2A
The series connection gives 10V or what?
The series connection gives 5V~@1A on each output

Some other relevant questions:
What does rms really mean? (Root mean square - 2*sqrt(2)*U?)
How do I calculate the value of a choke for my power supply or the need for one?
What should the current for a 15V power supply for a relay be? It doesn't say that on the board.

Thanks

 

[k7elp60]

The output from the transformer is RMS. With the two windings in parallel you will get 5V rms @ 2A. Both windings are in phase.
With the two windings in series you will get 10V rms @ 1A when using the two outside legs.
When tying the two center legs together you will get 5V rms between either outside leg and the centertap @ 1A. The two outside legs are out of phase with each other.

 

[Nigel Goodwin]

Hi There,

Making a stabilized power supply for my PIC development board lead me to a datasheet for the Tamura Power transformer PL10-10-130B:

**broken link removed**

In the table for output voltage there is a strange description for the series connection. It says 10.0CT (Centertap). Does that mean, that I get 5V from both outputs, if I use one of the pins as output and ground the centertap? Why is it described like so and not by 2x5.0V?

The parallel connection gives 5V~@2A
The series connection gives 10V or what?
The series connection gives 5V~@1A on each output

Some other relevant questions:
What does rms really mean? (Root mean square - 2*sqrt(2)*U?)
How do I calculate the value of a choke for my power supply or the need for one?
What should the current for a 15V power supply for a relay be? It doesn't say that on the board.

The transformer has two 5V windings, you can put them in parallel for 5V at twice the current (2A), or in series for 10V at single current (1A).

Chokes haven't been used in PSU's since the 1950's, you use decent size electrolytics and a regulator.