Current rating for transformer is it enough

[amateur_24]

Hi
Say I have two components that source 200MA of current each. Do I need a transformer that's capable of delivering 400ma or 200ma?

 

[DerStrom8]

Hi, amateur_24. I think you might have your vocabulary mixed up. Do you mean two components that SINK 200mA each? If they source it, it means they deliver it.
If you plan on running both at once in parallel with your power supply, your supply will have to SOURCE at least 400mA.

 

[amateur_24]

Sorry I meant they each require 200ma to function so that's SINK right?

This transformer will need to be rectified to DC current because of my LCD and AVR microcontroller. Is the maximum rms value of the rectifier the maximum ac voltage you can supply it?

 

[DerStrom8]

Sorry I meant they each require 200ma to function so that's SINK right?

This transformer will need to be rectified to DC current because of my LCD and AVR microcontroller. Is the maximum rms value of the rectifier the maximum ac voltage you can supply it?

If they each require 200mA, then that is how much current they draw, or sink. Yes, that is right.

Yes, the voltage rating of the rectifier is the maximum input voltage. Exceeding this value may, and probably will, damage the rectifier.
Der Strom

 

[amateur_24]

Thanks for answering my newbie questions. I was never taught electronics. I relised the best way to learn is to get your hands dirty.

 

[crutschow]

For a rectifier load you will need a transformer rated at a higher current then the load since the short, high current pulses drawn from the transformer by the rectifier circuit cause higher I²R heating then a resistive load. I would recommend a transformer rated for at least 150% of the maximum DC load or 600mA for a 400mA dc load.

 

[amateur_24]

Thanks for that info crutschow. I'll get myself a 0.67A transformer. The above was an example.