hamzahaider
Newbie level 4
I am working to make a power supply with Ups backup. Im still learning different things about making a power supply. However currently i am trying to chose an appropriate transformer size.
my load would be
1) 5v, 2A
2) 12v, 2A.
Some one told me that a transformer 220vac to 18vac rated at 3A would be more than enough. However when I used Isis protues to simulate the current being drawn, the ac current rose to above 4A on a 15v 2A lamp which equals 30W. The DC current being drawn was however 1.6A after being rectified which makes sense at around 18v it almost equals 30W.
Now i am confused on how big a transformer should i use.
Ive attached a jpeg of the simulation for reference.
Any sort of help is well appreciated so thank you in advance.
my load would be
1) 5v, 2A
2) 12v, 2A.
Some one told me that a transformer 220vac to 18vac rated at 3A would be more than enough. However when I used Isis protues to simulate the current being drawn, the ac current rose to above 4A on a 15v 2A lamp which equals 30W. The DC current being drawn was however 1.6A after being rectified which makes sense at around 18v it almost equals 30W.
Now i am confused on how big a transformer should i use.
Ive attached a jpeg of the simulation for reference.
Any sort of help is well appreciated so thank you in advance.