---------------------------------------------------------- AeroElectric-List Digest Archive --- Total Messages Posted Tue 12/14/10: 14 ---------------------------------------------------------- Today's Message Index: ---------------------- 1. 12:19 AM - 2010 List of Contributors (Matt Dralle) 2. 07:17 AM - Re: Computing a Resistor Value (Noel Loveys) 3. 07:37 AM - Re: Computing a Resistor Value (Ken) 4. 07:53 AM - Noise from Garmin 496 (Marty) 5. 07:57 AM - Re: Computing a Resistor Value (Noel Loveys) 6. 08:16 AM - Re: Noise from Garmin 496 (Daniel Hooper) 7. 08:56 AM - Re: Computing a Resistor Value (Noel Loveys) 8. 09:27 AM - Re: Computing a Resistor Value (Robert L. Nuckolls, III) 9. 09:43 AM - Re: Computing a Resistor Value (Robert L. Nuckolls, III) 10. 09:54 AM - Re: Computing a Resistor Value (RGent1224@aol.com) 11. 04:44 PM - Re: Computing a Resistor Value (AlRice) 12. 07:33 PM - Re: Computing a Resistor Value (Robert L. Nuckolls, III) 13. 08:48 PM - Re: Computing a Resistor Value (RGent1224@aol.com) 14. 09:41 PM - Re: Computing a Resistor Value (Bob McCallum) ________________________________ Message 1 _____________________________________ Time: 12:19:50 AM PST US From: Matt Dralle Subject: AeroElectric-List: 2010 List of Contributors Dear Listers, The 2010 Matronics Email List and Forum Fund Raiser officially ended a couple of weeks ago and its time that I publish this year's List of Contributors. Its the people on this list that directly make the Email Lists and Forums possible. Their generous contributions keep the servers and Internet connection up and running. You can still show your support this year and pick up a great gift at the same time. The Contribution Web Site is fast, easy, and secure: http://www.matronics.com/contribution Or, by dropping a personal check in the mail to: Matt Dralle / Matronics 581 Jeannie Way Livermore CA 94550 I also want to thank Bob, Jon, and Andy for their generous support through the supply of great gifts this year!! These guys have some great products and I encourage you to visit their respective web sites: Bob Nucklolls - AeroElectric - www.aeroelectric.com Jon Croke - HomebuiltHELP - www.homebuilthelp.com Andy Gold - The Builder's Bookstore - www.buildersbooks.com And finally, I'm proud to present The 2010 Fund Raiser List of Contributors: http://www.matronics.com/loc/2010.html Thanks again to everyone that made a Contribution this year!! Matt Dralle Matronics Email List and Forum Administrator ________________________________ Message 2 _____________________________________ Time: 07:17:07 AM PST US From: "Noel Loveys" Subject: RE: AeroElectric-List: Computing a Resistor Value First thing you want to do is build a solid state voltage regulator for a 5V output.IK can't remember the number on the chip but they are available at Radio Scrap. The back of the package has a usable schematic. Noel -----Original Message----- From: owner-aeroelectric-list-server@matronics.com [mailto:owner-aeroelectric-list-server@matronics.com] On Behalf Of AlRice Sent: December 12, 2010 10:30 PM Subject: AeroElectric-List: Computing a Resistor Value I want to install my AV80R GPS in my panel and wire the power lead to the bus without installing a clunky cigarette power socket on my panel. The GPS input voltage is 5V and it draws 1.5A (at least that's what the cigarette power lead says on it). My buss voltage is 13.5V, so how do I compute the resistor ohm's and watts needed for my power lead? I know enough about Ohm's law to be dangerous. Thanks. -------- Al Rice Skybolt 260 RV-9A Helping with my grandson's Piet Read this topic online here: http://forums.matronics.com/viewtopic.php?p=323122#323122 ________________________________ Message 3 _____________________________________ Time: 07:37:00 AM PST US From: Ken Subject: Re: AeroElectric-List: Computing a Resistor Value 7805 and LM350 for higher current come to mind. Ken do not archive Noel Loveys wrote: > > First thing you want to do is build a solid state voltage regulator for a 5V > output.IK can't remember the number on the chip but they are available at > Radio Scrap. > The back of the package has a usable schematic. > > Noel > ________________________________ Message 4 _____________________________________ Time: 07:53:37 AM PST US Subject: AeroElectric-List: Noise from Garmin 496 From: Marty Thanks to Kevin K and Dave S for their replies. Seems like some installations may have noise and others not. I'll try disconnecting the power line next visit to the airport, but we're "frozen" in here in Nashville TN. If that works, I suspect there is some "output" from my 496 that is generating the noise. Pulling the power input line, which also has the power outputs will give some clues that it is in the 496 output side versus perhaps the weather antenna. My GPS output signal is split into three (max per Garmin) to feed my Dynon D10A, Electronic International Fuel Totalizer, and the third device escapes me right now, perhaps its the EI SuperClock. I also feed the output to Garmin's SL30 radio to feed the com and nav frequencies, and the warnings to my Garmin Audio Panel. Waiting now for warmer weather to go do some testing! Thanks again folks for your thoughts. Marty N826ME RV-6A ________________________________ Message 5 _____________________________________ Time: 07:57:02 AM PST US From: "Noel Loveys" Subject: RE: AeroElectric-List: Computing a Resistor Value Only problem with that is resistors don't drop voltage unless they are set up in a voltage divider network. They only restrict current. Don't believe me? Ok.... Try this; take a convenient battery and measure the voltage across the terminals. Then connect any resistor to one terminal of the voltmeter and take another reading. Guess what both readings will be the same! Now to check the current flow. Connect a nice hefty resistor to one terminal of the battery and using a suitable ammeter measure the current through the resistor. Then add a resistor to one terminal of the ammeter and read again.... The second reading will be less than the first one indicating the resistor has actually dropped the current. If you are unsure of the resistor sizes to try use a battery tester and a resistor to do this experiment. If you want to build a voltage divider network with two resistors then that is another ball of wax. The problem with that is the network loads your buss the whole time it is active and it will load your buss. A solid state voltage regulator on the other hand will also load your buss but to a much less degree. Early model 45 field radios used a voltage divider network to give low power capability to the transmitters. It wasn't long before operators noticed the batteries didn't last jig time if the transmitter was operated on low power mode. Noel -----Original Message----- From: owner-aeroelectric-list-server@matronics.com [mailto:owner-aeroelectric-list-server@matronics.com] On Behalf Of Richard E. Tasker Sent: December 13, 2010 1:11 AM Subject: Re: AeroElectric-List: Computing a Resistor Value Just adding a resistor is probably not a good idea. A resistor drops a variable amount of voltage depending on the actual current consumption. Additionally, your bus voltage will vary from 12V or less when the alternator is off to as much as 14.2V when it is on. Unless the AV80R draws a constant current (unlikely) and can handle a relatively wide voltage input, you really do need to use the power cord or some other source of 5V. I couldn't find a manual to see what voltage it can handle, but given they sell adapters for 12/24VDC and for 110/220VAC, it is likely that it can use only a limited voltage (5V). The markings on the adapter almost surely refer to the adapter capacity, not the exact consumption of the AV80R. For educational purposes, assuming that the AV80R actually did take exactly 1.5A at 5V and your buss voltage was a constant 13.5V, you would calculate the resistor value as follows: The resistor would have to drop 13.5V minus 5V or 8.5V at 1.5A. Since V=I*R or R=V/I, then R = 8.5V/1.5A or 5.666 ohms which is close to a standard 5.6 ohm resistor. If we used that resistor we would actually get 8.4V drop which gives us 5.1V for the AV80R which would probably be close enough. The power dissipated in the resistor would be P=V*I or 8.4V*1.5A = 12.6W which would mean it would have to be a pretty large wirewound ceramic resistor that would get mighty hot. Of course, all this is based on the paragraph above this one, which is highly unlikely. You can either find a 12V to 5V power converter to include behind the panel or just use the optional cigarette lighter adapter provided by Honeywell. Dick Tasker AlRice wrote: > --> AeroElectric-List message posted by: "AlRice" > > I want to install my AV80R GPS in my panel and wire the power lead to the bus without installing a clunky cigarette power socket on my panel. The GPS input voltage is 5V and it draws 1.5A (at least that's what the cigarette power lead says on it). My buss voltage is 13.5V, so how do I compute the resistor ohm's and watts needed for my power lead? I know enough about Ohm's law to be dangerous. > Thanks. > > -------- > Al Rice > Skybolt 260 > RV-9A > Helping with my grandson's Piet > > > Read this topic online here: > > http://forums.matronics.com/viewtopic.php?p=323122#323122 > > > -- Please Note: No trees were destroyed in the sending of this message. We do concede, however, that a significant number of electrons may have been temporarily inconvenienced. -- ________________________________ Message 6 _____________________________________ Time: 08:16:35 AM PST US Subject: Re: AeroElectric-List: Noise from Garmin 496 From: Daniel Hooper Easier than disconnecting the power line, does it make the noise after it is fully charged? Some consumer devices with Li+ batteries have a habit of hammering the power line with noise while charging. It sounds like you have a lot of possible ground paths for the Garmin. Any of these can cause the charging return current to take an unwanted, roundabout path back to the battery. Additionally, if your audio output is single-ended (Audio+ to signal, Audio- to ground) large (by comparison) power currents can cause the unit to 'float' a bit from ground potential. When the power current varies, the 'floats' are cyclical, and you could hear it as noise. Hope that helps! --Daniel On Tue, Dec 14, 2010 at 9:50 AM, Marty wrote: > Thanks to Kevin K and Dave S for their replies. Seems like some > installations may have noise and others not. I'll try disconnecting the > power line next visit to the airport, but we're "frozen" in here in > Nashville TN. If that works, I suspect there is some "output" from my 496 > that is generating the noise. Pulling the power input line, which also has > the power outputs will give some clues that it is in the 496 output side > versus perhaps the weather antenna. > My GPS output signal is split into three (max per Garmin) to feed my Dynon > D10A, Electronic International Fuel Totalizer, and the third device escapes > me right now, perhaps its the EI SuperClock. I also feed the output to > Garmin's SL30 radio to feed the com and nav frequencies, and the warnings to > my Garmin Audio Panel. > Waiting now for warmer weather to go do some testing! Thanks again folks > for your thoughts. > Marty N826MERV-6A > > -- Daniel Hooper ________________________________ Message 7 _____________________________________ Time: 08:56:49 AM PST US From: "Noel Loveys" Subject: RE: AeroElectric-List: Computing a Resistor Value Yes... but another answer would be to us a circuit with more current capability. Or possibly using the 7805 to switch a power transistor. Noel From: owner-aeroelectric-list-server@matronics.com [mailto:owner-aeroelectric-list-server@matronics.com] On Behalf Of Mike Welch Sent: December 13, 2010 10:39 AM Subject: RE: AeroElectric-List: Computing a Resistor Value > The GPS input voltage is 5V and it draws 1.5A (at least that's what the >cigarette power lead says on it). My buss voltage is 13.5V, so how do I compute >the resistor ohm's and watts needed for my power lead?I know enough about >Ohm's law to be dangerous. > Thanks. > -------- > Al Rice Mornin' Al, When I first read your post, I didn't think the resistor was the way to go, either, same as Dick Tasker described. My thinking was you're asking quite a bit from just one resistor. My initial thought was "why not build a 5 volt circuit" (like this one)? http://www.tkk.fi/Misc/Electronics/circuits/psu_5v.html Recently, I asked this forum if they knew how I could turn my Ray Allen servo resistance output (0-5K ohms) into a visual LED indicator. Our buddy Joe Gores offered the perfect suggestion of a circuit referenced from Mike Linse. Included in his suggestion was that really handy 5 volt circuit above, plus it is super easy to build. The circuit had a final voltage output of 4.96 volts, and when combined with the circuit Mike Linse talked about, the whole project worked exactly as I was hoping for. From the article's data points about this 5 volt circuit, it says it may be limited to only one amp, plus you should consider a heat sink. So I got to thinking......... Here's a question for for you guys that rearrange electrons for a living.....could a guy build TWO of these 5 volt circuits, and combine the '5 volt output' in parallel? Mike Welch ________________________________ Message 8 _____________________________________ Time: 09:27:07 AM PST US From: "Robert L. Nuckolls, III" Subject: RE: AeroElectric-List: Computing a Resistor Value At 09:12 AM 12/14/2010, you wrote: > >First thing you want to do is build a solid state voltage regulator for a 5V >output.IK can't remember the number on the chip but they are available at >Radio Scrap. >The back of the package has a usable schematic. This is also an option. The 3-terminal regulators are factory calibrated step-down voltage control devices. http://www.fairchildsemi.com/ds/LM/LM7805.pdf Unlike the "smart weight" I described earlier, these are more like "smart valves". Instead of working in PARALLEL with the output load, these work in SERIES. They have a distinct advantage for optimizing power dissipation (waste heat). As we studied in the Zener example, loads on the input power supply are constant irrespective of load demanded by the powered-up device. This is the least efficient means by which step down voltage tasks can be managed but they are SIMPLE. So you use them only in the smallest of situations were waste energy is not a significant design concern. The series-pass 3-terminal regulators will draw power from the supply that is only a few microamps more than the load demanded by the load. They are also easily adjusted. I used to offer a line of panel light dimmers based on 3-terminal devices. http://www.aeroelectric.com/Catalog/AEC/9013/ Note that the larger the anticipated loads, the larger the device AND it's associated heatsink. Now, if you don't mind taking the hit in terms of size, weight and disspated power, this technology offers a simple, low noise and relatively inexpensive means for acquiring a very high-quality (meaning low noise) DC power source for devices needing 9 volts and less. This 9-volt limitation is due to the need for 'headroom' in the difference between input and output voltages. If you want the device to deliver, say 12 volts constant output, the INPUT cannot be lower than about 13.5 volts. A 9v design goal for output can be achieved for inputs down to about 10.5 volts. Bob . . . >Noel > >-----Original Message----- >From: owner-aeroelectric-list-server@matronics.com >[mailto:owner-aeroelectric-list-server@matronics.com] On Behalf Of AlRice >Sent: December 12, 2010 10:30 PM >To: aeroelectric-list@matronics.com >Subject: AeroElectric-List: Computing a Resistor Value > > >I want to install my AV80R GPS in my panel and wire the power lead to the >bus without installing a clunky cigarette power socket on my panel. The GPS >input voltage is 5V and it draws 1.5A (at least that's what the cigarette >power lead says on it). My buss voltage is 13.5V, so how do I compute the >resistor ohm's and watts needed for my power lead? I know enough about >Ohm's law to be dangerous. >Thanks. > >-------- >Al Rice >Skybolt 260 >RV-9A >Helping with my grandson's Piet > > >Read this topic online here: > >http://forums.matronics.com/viewtopic.php?p=323122#323122 > > >----- >No virus found in this message. >Checked by AVG - www.avg.com Bob . . . ________________________________ Message 9 _____________________________________ Time: 09:43:18 AM PST US From: "Robert L. Nuckolls, III" Subject: RE: AeroElectric-List: Computing a Resistor Value Mornin' Al, When I first read your post, I didn't think the resistor was the way to go, either, same as Dick Tasker described. My thinking was you're asking quite a bit from just one resistor. My initial thought was "why not build a 5 volt circuit" (like this one)? http://www.tkk.fi/Misc/Electronics/circuits/psu_5v.html Recently, I asked this forum if they knew how I could turn my Ray Allen servo resistance output (0-5K ohms) into a visual LED indicator. Our buddy Joe Gores offered the perfect suggestion of a circuit referenced from Mike Linse. Included in his suggestion was that really handy 5 volt circuit above, plus it is super easy to build. The circuit had a final voltage output of 4.96 volts, and when combined with the circuit Mike Linse talked about, the whole project worked exactly as I was hoping for. From the article's data points about this 5 volt circuit, it says it may be limited to only one amp, plus you should consider a heat sink. So I got to thinking......... Here's a question for for you guys that rearrange electrons for a living.....could a guy build TWO of these 5 volt circuits, and combine the '5 volt output' in parallel? Sure . . . or go to a bigger device. The 3-terminal regulators come in a range of sizes. The smallest are Emacs! 6 x 4 mm on a side, solder right to the board, and as you might expect, cannot dissipate much power. They're good for 100-500 mA max . . . but if your needs are small . . . At the other end of the spectrum, you can buy these guys Emacs! Rated for 5A and MUST be on a hefty heatsink. Furhter, one can built arrays of transistors on even heftier heatsinks perhaps cooled with fans. Emacs! I think the last time I built up something like this it was to craft a finely adjustable 50A, 28v load bank. There were 10 fat transistors on a big chunk of aluminum cooled with a fan. This rig was good for 1400 watts of room warming dissipation all controlled by a little piece of plastic Emacs! and a 1/2" diameter potentiometer. The point to be made here is that the series-pass, smart regulator can be crafted in just about any size and output voltage within ratings limits for the devices. Bob . . . ________________________________ Message 10 ____________________________________ Time: 09:54:29 AM PST US From: RGent1224@aol.com Subject: Re: AeroElectric-List: Computing a Resistor Value Bob Did you include a bunch of photos that Yahoo didn't like?? Just a wondering Dick In a message dated 12/14/2010 11:44:25 A.M. Central Standard Time, nuckolls.bob@aeroelectric.com writes: Mornin' Al, When I first read your post, I didn't think the resistor was the way to go, either, same as Dick Tasker described. My thinking was you're asking quite a bit from just one resistor. My initial thought was "why not build a 5 volt circuit" (like this one)? _http://www.tkk.fi/Misc/Electronics/circuits/psu_5v.html _ (http://www.tkk.fi/Misc/Electronics/circuits/psu_5v.html) Recently, I asked this forum if they knew how I could turn my Ray Allen servo resistance output (0-5K ohms) into a visual LED indicator. Our buddy Joe Gores offered the perfect suggestion of a circuit referenced from Mike Linse. Included in his suggestion was that really handy 5 volt circuit above, plus it is super easy to build. The circuit had a final voltage output of 4.96 volts, and when combined with the circuit Mike Linse talked about, the whole project worked exactly as I was hoping for. >From the article's data points about this 5 volt circuit, it says it may be limited to only one amp, plus you should consider a heat sink. So I got to thinking......... Here's a question for for you guys that rearrange electrons for a living.....could a guy build TWO of these 5 volt circuits, and combine the '5 volt output' in parallel? Sure . . . or go to a bigger device. The 3-terminal regulators come in a range of sizes. The smallest are 6 x 4 mm on a side, solder right to the board, and as you might expect, cannot dissipate much power. They're good for 100-500 mA max . . . but if your needs are small . . . At the other end of the spectrum, you can buy these guys Rated for 5A and MUST be on a hefty heatsink. Furhter, one can built arrays of transistors on even heftier heatsinks perhaps cooled with fans. I think the last time I built up something like this it was to craft a finely adjustable 50A, 28v load bank. There were 10 fat transistors on a big chunk of aluminum cooled with a fan. This rig was good for 1400 watts of room warming dissipation all controlled by a little piece of plastic and a 1/2" diameter potentiometer. The point to be made here is that the series-pass, smart regulator can be crafted in just about any size and output voltage within ratings limits for the devices. Bob . . . ________________________________ Message 11 ____________________________________ Time: 04:44:27 PM PST US Subject: AeroElectric-List: Re: Computing a Resistor Value From: "AlRice" So, like I said, I chickened out and decided to use the car charger unit that came with the AV80R. I was able to pry the case apart and inside was a 1"x1" 12v-5v DC to DC power converter. I cut off the leads to the outside contacts and soldered on longer leads. For a case for the power converter, I simply used the existing one and routed the leads out the nose to a Molex plug. I'll secure the case behind the panel with an Adel clamp. Here is what it looks like. -------- Al Rice Skybolt 260 RV-9A Helping with my grandson's Piet Read this topic online here: http://forums.matronics.com/viewtopic.php?p=323386#323386 Attachments: http://forums.matronics.com//files/img_0001_533.jpg ________________________________ Message 12 ____________________________________ Time: 07:33:49 PM PST US From: "Robert L. Nuckolls, III" Subject: Re: AeroElectric-List: Computing a Resistor Value At 11:50 AM 12/14/2010, you wrote: >Bob >Did you include a bunch of photos that Yahoo didn't like?? >Just a wondering >Dick > I guess I don't understand the question. Are you having trouble seeing the images? You echoed the posting back to me and they all appear as I originally sent them. Bob . . . ________________________________ Message 13 ____________________________________ Time: 08:48:19 PM PST US From: RGent1224@aol.com Subject: Re: AeroElectric-List: Computing a Resistor Value All I got was blanks where a photo was supposed to be aka Blanks Dick In a message dated 12/14/2010 9:35:34 P.M. Central Standard Time, nuckolls.bob@aeroelectric.com writes: At 11:50 AM 12/14/2010, you wrote: Bob Did you include a bunch of photos that Yahoo didn't like?? Just a wondering Dick I guess I don't understand the question. Are you having trouble seeing the images? You echoed the posting back to me and they all appear as I originally sent them. Bob . . . (http://www.aeroelectric.com/) (http://www.buildersbooks.com/) (http://www.homebuilthelp.com/) (http://www.matronics.com/contribution) (http://www.matronics.com/Navigator?AeroElectric-List) ________________________________ Message 14 ____________________________________ Time: 09:41:07 PM PST US From: Bob McCallum Subject: RE: AeroElectric-List: Computing a Resistor Value Dick; All of the pictures in both Bob's original and your reply to him worked fine for me. No blanks. Must have something to do with your computer settings. Bob McC DO NOT ARCHIVE _____ From: owner-aeroelectric-list-server@matronics.com [mailto:owner-aeroelectric-list-server@matronics.com] On Behalf Of RGent1224@aol.com Sent: Tuesday, December 14, 2010 11:44 PM Subject: Re: AeroElectric-List: Computing a Resistor Value All I got was blanks where a photo was supposed to be aka Blanks Dick In a message dated 12/14/2010 9:35:34 P.M. Central Standard Time, nuckolls.bob@aeroelectric.com writes: At 11:50 AM 12/14/2010, you wrote: Bob Did you include a bunch of photos that Yahoo didn't like?? Just a wondering Dick I guess I don't understand the question. Are you having trouble seeing the images? You echoed the posting back to me and they all appear as I originally sent them. 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