I finished my core boards, on which I soldered the rectifier and the voltage regulator. If I now have a regulated 5V Power Supply, can I just connect it to J2, leaving the regulator and rectifier on the PCB or do I have do desolder the stuff?
THX and Greets
Roger
hi ,
as Seppoman said in another post , the regulator mounted on the core need at least 6,5v to deliver the 5v regulated current ,so you will have less than 5v after the regulator. if your power is regulated and in DC , i thinkyou can bypass the reg on the core.
this tread will be probably more clear:
if your power is regulated and in DC , i thinkyou can bypass the reg on the core.
… well, that was actually part of my question ;). By connecting the external regulated supply on J2, I would “bypass” the onboard rectifier and regulator.
But the question I asked was: Is it a problem, when the onboard stuff is still soldered to the PCB?
Greets, Roger
Hi Roger,
if you feed a regulated voltage on J2 without having the 7805 powered via J1, you normally shouldn’t be confronted with a big problem. But if this will be your future fixed configuraion, I’d suggest to desolder the 7805, just to avoid possible strange effects on load changes on the 5V line. It’s more clean to do this. Background: if you put a voltage on the output stage of an unpowered 7805, it might happen that you destroy his power output stage (depending on the supplier of the 7805) which could lead to a shortcut inside the 7805 – under very bad circumstances. And a shortcut between +5V and GND could consequently destroy your external power supply.
Cheers,
Skunk
Thanks Skunk
I desoldered the rectifier and the regulator as well as C5 + C6.
I left the bypass caps C3 + C4 on the board to filter possible ripple… that should be just fine, right?
Greets, Roger
Yep, should work fine that way.
Cheers,
Skunk