I was looking at this answer:
and I want to make sure that I understand...
I have a project that will be taking 120VAC current and turning it into 12VDC current using a Hi-Link HLK-PM12, which I need to switch a relay, and it will have a LD1117V33C to turn part of the 12VDC into 3.3VDC to run an ESP-01.
Now my question; the HLK-PM12 says that it's output is 12VDC, 3W.
According to the datasheet the LD1117 runs around 50C per Watt. I've been testing my circuit with a 9V battery, and the LD1117 gets a little warm, but not too bad. How exactly would I figure out how hot this thing might get with 12V 3W? If it's going to get up to 150C that's going to be a problem. Another problem is that this project is going to be outdoors, and so will be in a sealed project case, meaning while I can put a heat sink on, there won't be any air flow to help dissipate heat.
So how to I minimize heating with this?
Would a series of resisters between the HLK-PM12 and LD1117 drop the current enough to avoid a problem? If so, is this math correct?
I = P / C = 3W / 12V = .25A
And if so, what's the best way to figure out what resistors I'll need?
Another option would be to use a HLK-PM03 to turn 120VAC directly into 3.3VDC, and then I could avoid the whole LD1117 problem, but I don't know if that's necessary?
Please forgive me if I am misusing any terms. I'm something of a novice.
Edit: Plan B
Decided that the ESP8266-01 needs to have it's own power source, as there won't be enough current left over once the relay has been started.
So I came up with this schematic:
I'm hoping this will put me more on the right track.
Maybe this should be a new question at this point, as I've basically found out that my original plan won't work.