You can also run off 5 Alkaline batteries. Lasts a long time. I make dummy batteries for the pack out of a piece of 1/2" hardline. Looks cool and it's even marked "Dummy". 73 Kees K5BCQ
-- Jack Brindle <[EMAIL PROTECTED]> wrote: Let's amplify on what Tony said. In the circuit, if you are drawing 100 mA and running things from a 13.8V power supply, the useful circuit is using 0.5 watts of power. The regulator is dissipating 0.88 watts of power in heat. It's actually worse than this since the oscillator is running at 3.3 volts, so the 3.3 volt regulator is dissipating an additional 0.17 watts of power in the form of heat. It truly is a shame to burn up more power in a regulator than is used in the actual useful circuit. Now you know why switching regulators are used so much. Too bad they tend to generate noise we find objectionable in our receivers. On May 7, 2008, at 9:06 AM, Tony Parks wrote: > Hi Jim, > > Do you have a measurement of the current from the 13.8 volts power > supply when the v8.0 (?) is running on various bands? Also do you > have a temperature measurement on the 5 volt regulator? > > I think the typical current is around 100 mA for about 0.8 watts of > heat in the 5 volt TO220 case regulator. > > 73, > Tony KB9YIG > ----- Original Message ----- > From: James R. Elledge > To: [email protected] > Sent: Wednesday, May 07, 2008 10:59 AM > Subject: [softrock40] SR LITE V8.x SUGGESTION > > The 7805 VR gets a bit warm when using a 12V or 13.8V power supply, > another VR (9V perhaps) between the 12/13.8V PS would help. This > technique has been used successfully by others (and myself) to help > with the heat problem when using standard 12/13.8 PS's. > > Jim - KB2XJ > > > -Jack Brindle, W6FB =======================================================================
