I have been using ST-Micro L4940 LDO (.7v drop) 1.5A, TO220 voltage regulators on my board... Much better that the 7805, runs cooler that the 7805's and at Avnet Express, its a bit under $1 each...
I have also found that Avnet Express is alway cheaper that Mouser, Jamco or Digikey for most parts.... On Sat, Jul 19, 2014 at 9:47 AM, Gary Kaufman <[email protected]> wrote: > Josh - > > There's a tiny 1A switch mode voltage regulator on Ebay (Item > 261355553215) and directly on the seller's site: > > http://www.elabpeers.com/40v-to-5v-voltage-regulator-lm7805.html > > Looks like it might be a perfect fix for the problem here. I suspect the > problem isn't the 1A rating, but rather the thermal limitations of the > TO-220. > > I've ordered two and can report back once I receive them. I offered the > seller $9.50 each / quantity 2 with the ebay "Make an offer" and it was > quickly accepted. > > - Gary > > > On 7/19/2014 11:49 AM, John Monahan wrote: > > Just want to mention, people may want to consider using the 1.5A To-220 > regulators rather than the old 1A 7805’s. For example a L7805CV (Jameco > #924633). Indeed I seem to remember Mouser had 3A 5V’s in a TO-220 package. > > There are a lot of chips for one 7805 on that board. On a V2 version > Josh, you might want to consider a 3A LM232K, I know they are a real pain > to get, take up much more room, but they do run much cooler. > Alternatively put two To-220’s on the board. It’s probably just me, but I > don’t like hot boards. Over time the fiberglass starts to deform/change > color… minimally put a mica washer between the heat sink and board. Also > use heat sink paste. > > > > John > > > > > > *From:* [email protected] [mailto:[email protected] > <[email protected]>] *On Behalf Of *Crusty OMO > *Sent:* Saturday, July 19, 2014 5:34 AM > *To:* [email protected] > *Subject:* RE: [N8VEM-S100:4637] 8080 CPU - Heat is ON - Wet Finger Test > > > > Hi Guys, > > Because the 7805 can get hot, I want to just issue a safety warning for > everyone. > > Hopefully, most of you already know this, but just in case, it's always a > good idea to remind and inform the new comers. > > When powering a board for the first time, be ready to check the voltages > and monitor the heat of the regulator(s). > Cut power off at the sign of any trouble. > > When monitoring the heat of the regulator by finger, always use a wet > finger. Doesn't sound right near electricity, but hopefully you have a > properly grounded power supply and chassis. The wet finger will prevent > severe burns if the temperature is over 100c. When it's over 100c, a quick > light tap on the surface with a wet finger will give a quick sizzle. It's > like testing the temperature on your clothes iron. The best way is to use > an infrared surface thermometer, but I only got one of those a few months > ago. Up to now, I've always used the wet finger without incident. > > Regards, > Josh Bensadon > > -- > You received this message because you are subscribed to the Google Groups > "N8VEM-S100" group. > To unsubscribe from this group and stop receiving emails from it, send an > email to [email protected]. > For more options, visit https://groups.google.com/d/optout. > -- > You received this message because you are subscribed to the Google Groups > "N8VEM-S100" group. > To unsubscribe from this group and stop receiving emails from it, send an > email to [email protected]. > For more options, visit https://groups.google.com/d/optout. > > > -- > You received this message because you are subscribed to the Google Groups > "N8VEM-S100" group. > To unsubscribe from this group and stop receiving emails from it, send an > email to [email protected]. > For more options, visit https://groups.google.com/d/optout. > -- ~~ _/) ~~~~ _/) ~~~~ _/) ~~~~ _/) ~~ Tom Lafleur (858) 759-9692 -- You received this message because you are subscribed to the Google Groups "N8VEM-S100" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. For more options, visit https://groups.google.com/d/optout.
