hello everybody
I am sorry but I will ask some stupid questions...
the situation:
I have found a power supply that outputs 12v 1A .
I build a pcb with a 7805 and an LM317 to get outputs 3.3v 5V and 12v
when I connect a raspberry pi, the 7805 gets real hot(burned my finger)
so I tried to measure the current draw...and this is the stupid question...
first I moved the red cable of my multimeter into the 10A connector , set the select range on 200mA DC where 10A is mentionned
(I have a bk precision 2704c
I put the probes in serie and on the screen I get a max of "04.3"
Is it correct to assume 430mA ?
anyway, based on the assumption above, I tried to understand ...and here are my conclusions...am I right?
7805
Vin=12v
Vout=5v
drop=7v
pi current=0.43A
so the power is 7v * 0.43A=3.01W wich I guess is too much...?
again...stupid...what would be a solution for this problem?