As a reference point, if its temp is 120 def F or more you can't leave your finger on it, IIRC. Not very hot for an active electronic device. You can't rely on your fingers to tell you what is too hot in a circuit.
Jerry W4UK At 05:47 PM 5/7/2008, you wrote: >I mis-spoke, the TO-220 package is rated to dissipate a watt with no >heat sink at only 70C. at 25C it can dissipate around 2 watts. Still >way more than it's dissipating in this application. > >Dale, >NV8U > >Dale J. Robertson wrote: >> >>Jim, >>If you can touch the VR it's not even close to too hot! >>that thing is rated to dissipate a watt with no heat sink at 100C >>ambient (room) temp. >>Dale >>NV8U >> >>James R. Elledge wrote: >>> >>>--- In >>><mailto:softrock40%40yahoogroups.com>[email protected], >>>"Tony Parks" <[EMAIL PROTECTED]> 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: <mailto:softrock40%40yahoogroups.com>[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 >>> > >>>Hi Tony >>> >>>I do not have a temp probe for accurate measurements (use my finger). >>>The VR is not exactly HOT but a bit warm to me. A small HS may fit >>>under the reg to keep me from getting excited. The Si chip also a >>>bit warm after a few minutes of op. I can get an accurate current >>>reading, 98.54 mA at 12.0V (default freq). Only checked output at the >>>default freq, its ok. Need to locate the sw's settings vs output >>>freq , will look in files to locate. >>> >>>I will make a chart for freq vs current when I can (dog sitting/house >>>sitting for the next four or five days-sister out of town). >>> >>>Jim - KB2XJ > >
