DC transformer amps.

[hartly]

Why does my 9v D.C. transformer only give a max. amps. of 0.22A?.
I've looked inside it and it doesnt seen to have any resistor in
series to restrict the current.
A 6v. battery charger can give out 4 amps.,which proves its nothing
to do with the voltage of input or output.
Thanks.

 

[Andrew Holme]

hartly wrote:

Why does my 9v D.C. transformer only give a max. amps. of 0.22A?.
I've looked inside it and it doesnt seen to have any resistor in
series to restrict the current.
A 6v. battery charger can give out 4 amps.,which proves its nothing
to do with the voltage of input or output.
Thanks.

It'll be the rating of the transformer and/or the rectifier diodes.
The transfomer core can only handle so much magnetic flux before it
satures. The windings have resistance and dissipate heat. There are
Eddy currents that also generate heat. The bridge rectifier diodes
will be of a similar rating to the transformer. I should imagine your
battery charger is larger and heavier.

 

[hartly]

Thanks Andreww, and others.
My low current transformer does have 2 diodes in the circuit, but I
hadnt realized that they also restrict amps like a resistor does.
So that must be why it gives only 0.22 A


Hartly.


"Andrew Holme" <ajholme@hotmail.com> wrote in message news:<1114787824.091029.257650@f14g2000cwb.googlegroups.com>...

hartly wrote:
Why does my 9v D.C. transformer only give a max. amps. of 0.22A?.
I've looked inside it and it doesnt seen to have any resistor in
series to restrict the current.
A 6v. battery charger can give out 4 amps.,which proves its nothing
to do with the voltage of input or output.
Thanks.

It'll be the rating of the transformer and/or the rectifier diodes.
The transfomer core can only handle so much magnetic flux before it
satures. The windings have resistance and dissipate heat. There are
Eddy currents that also generate heat. The bridge rectifier diodes
will be of a similar rating to the transformer. I should imagine your
battery charger is larger and heavier.