Current rating for a transformer

Thread Starter

kdillinger

Joined Jul 26, 2009
141
I have a stupid question about transformers. I am working on another project that interfaces a power amplifier to the electrical mains via a transformer.
I am researching Google and looking back through my old books to find a current rating or something that is equivalent. So far there are failures and not much else is known at the moment.
The transformer the other team is using is "rated at 200mA" and the power amplifier in the application can deliver 2A.
This immediately seems to be the problem, but I am a transformer neophyte and have no idea of there is a current rating similar to a resistor. Any tips while I am researching?

-Ken
 

GetDeviceInfo

Joined Jun 7, 2009
2,196
Most suppliers of smaller transformers will report thier secondary current. Transformers will be rated in VA, or Volt Amps. You divide this by your secondary voltage to arrive at it's current capabilities.
 

bountyhunter

Joined Sep 7, 2009
2,512
Small transformers have a secondary rating given in in RMS Volts and RMS current. They are specified assuming a resistive load, although that is rarely how they are used. BTW: transformer RMS current is always much higher than DC load current following a rectifier/capacitor: if you use a full wave bridge rectifier, transformer current is about 1.8X DC load current.
 
Top