Re: uBitxV6 -by transmitting resets-
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I've been shouted down about using diodes in this way on other forums, but I still thing it is an easy solution to a potential problem, and it has the added advantage of preventing reverse polarity accidents in some situations. Gordon and Ted are right; inline diodes do not produce noise unlike some other regulators. They are also ham-price-friendly AKA CHEAP! Daisy chain 5 and you are placing ~10-11 volts instead of 13.8 on the front end of that 7805, so it only has to deal with 60-70% (math done in my head) of the heat dissipation for a given current. 73 de Lee KX4TT On Tuesday, March 4, 2025 at 12:17:08 PM EST, Ted via groups.io <k3rta@...> wrote:
Hello, Pieter. ? I gather from commentary so far, that your 7805 is overheating from having to regulate down from 13.8 (down to 5v).? I don't have that problem and it may simply be that I have a heat sink on that regulator but I also have (what I believe is) a 10-ohm resistor in line with the B+ supply to the 7805. Thus, the ideas presented above to add diodes to the input of this regulator has merit. Dropping about 0.6v X 3 might help your regulator work less than it done at present.? As diodes are fairly cheap, use 4 if you like, even 5.? ? I've got a few of the other form of voltage regulators and have yet to substitute one for the 7805 - though I've experimented for the radio supply itself and noticed no added RF noise.? ? ? 72, ? Ted K3RTA ? ? |
Lee