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5Vdc U3S

[email protected] #20159 Can anyone suggest a reliable/stable 5dc P/S for U3S? 73 N1VIN? Vince
Roger Hill All Messages By This Member #20161 Hi Vince I used this Raspberry Pi psu from Amazon. I cut the micro usb plug off the end, and also used a 4700uF capacitor across the power terminals inside the U3S case. It worked fine. I have since replaced it with a home brew LM317 regulator arrangement, so I now feed the U3S with 12volts from my 'used for everything' power supply, and regulated it to 5 volts. That also works well, even though the LM317 gets quite hot. What that also does is let me use the 12V supply to feed the BS170's, but I have not done that yet. Roger G3YTN --- Roger Hill toggle quoted message Show quoted text On 2018-01-01 14:46, V Zecchinelli wrote: Can anyone suggest a reliable/stable 5dc P/S for U3S? 73 N1VIN? Vince
Frank W1FRA Member Profile All Messages By This Member #20163 For years, I have gone to the local Transfer Station, ie the Dump, and simply collected cell phone chargers, all 5VDC, and especially the newer Motorola ones, very stable. Free, get to know the people working there, and they will even save them for you. And free. I especially like the ones that are used with Fisjer Price toys. They are rugged, and very stable. Frank? ?W1FRA toggle quoted message Show quoted text On Mon, Jan 1, 2018 at 10:25 AM, Roger Hill <rhill@...> wrote: Hi Vince I used this Raspberry Pi psu from Amazon. I cut the micro usb plug off the end, and also used a 4700uF capacitor across the power terminals inside the U3S case. It worked fine. I have since replaced it with a home brew LM317 regulator arrangement, so I now feed the U3S with 12volts from my 'used for everything' power supply, and regulated it to 5 volts. That also works well, even though the LM317 gets quite hot. What that also does is let me use the 12V supply to feed the BS170's, but I have not done that yet. Roger G3YTN --- Roger Hill On 2018-01-01 14:46, V Zecchinelli wrote: Can anyone suggest a reliable/stable 5dc P/S for U3S? 73 N1VIN? Vince
Roger Hill All Messages By This Member #20164 开云体育 Hi Frank. That's what I did to start with...I took an old 5 volt phone charger and used it. But then I was having drift problems with the U3S? - it was gradually increasing frequency with use, ending up about 100Hz high from the dial frequency -? and finally discovered that my '5 volt' charger was producing 6.68 volts ...very stable, but very high! Changing that out for the one I mentioned earlier, which was very steady at 5.01 volts by my meter, fixed my drift problem. Roger G3YTN --- Roger Hill toggle quoted message Show quoted text On 2018-01-01 15:33, Frank W1FRA wrote: For years, I have gone to the local Transfer Station, ie the Dump, and simply collected cell phone chargers, all 5VDC, and especially the newer Motorola ones, very stable. Free, get to know the people working there, and they will even save them for you. And free. ? I especially like the ones that are used with Fisjer Price toys. They are rugged, and very stable. ? Frank? ?W1FRA On Mon, Jan 1, 2018 at 10:25 AM, Roger Hill <rhill@...> wrote: Hi Vince I used this Raspberry Pi psu from Amazon. I cut the micro usb plug off the end, and also used a 4700uF capacitor across the power terminals inside the U3S case. It worked fine. I have since replaced it with a home brew LM317 regulator arrangement, so I now feed the U3S with 12volts from my 'used for everything' power supply, and regulated it to 5 volts. That also works well, even though the LM317 gets quite hot. What that also does is let me use the 12V supply to feed the BS170's, but I have not done that yet. Roger G3YTN --- Roger Hill On 2018-01-01 14:46, V Zecchinelli wrote: Can anyone suggest a reliable/stable 5dc P/S for U3S? 73 N1VIN? Vince
Frank W1FRA Member Profile All Messages By This Member #20165 Yes, I have had that problem, especially with the older phone chargers. But many of the newer ones, are fine. I usually give them a light load and watch the output for a while.? I have had times when I returned from the dump with 20+ in a bag, checked them, and threw 15 back. But the price is right!? ?The same source works for displays if you play with Arduino stuff. The Nokia phones come apart easily and the display is the same on sold by many of the vendors.? ?I don't pick the dump like I used to, but some things are just too convenient and cheap ! Also small motors and switch toggle quoted message Show quoted text On Mon, Jan 1, 2018 at 10:48 AM, Roger Hill <rhill@...> wrote: Hi Frank. That's what I did to start with...I took an old 5 volt phone charger and used it. But then I was having drift problems with the U3S? - it was gradually increasing frequency with use, ending up about 100Hz high from the dial frequency -? and finally discovered that my '5 volt' charger was producing 6.68 volts ...very stable, but very high! Changing that out for the one I mentioned earlier, which was very steady at 5.01 volts by my meter, fixed my drift problem. Roger G3YTN --- Roger Hill On 2018-01-01 15:33, Frank W1FRA wrote: For years, I have gone to the local Transfer Station, ie the Dump, and simply collected cell phone chargers, all 5VDC, and especially the newer Motorola ones, very stable. Free, get to know the people working there, and they will even save them for you. And free. ? I especially like the ones that are used with Fisjer Price toys. They are rugged, and very stable. ? Frank? ?W1FRA On Mon, Jan 1, 2018 at 10:25 AM, Roger Hill <rhill@...> wrote: Hi Vince I used this Raspberry Pi psu from Amazon. I cut the micro usb plug off the end, and also used a 4700uF capacitor across the power terminals inside the U3S case. It worked fine. I have since replaced it with a home brew LM317 regulator arrangement, so I now feed the U3S with 12volts from my 'used for everything' power supply, and regulated it to 5 volts. That also works well, even though the LM317 gets quite hot. What that also does is let me use the 12V supply to feed the BS170's, but I have not done that yet. Roger G3YTN --- Roger Hill On 2018-01-01 14:46, V Zecchinelli wrote: Can anyone suggest a reliable/stable 5dc P/S for U3S? 73 N1VIN? Vince
k1iff All Messages By This Member #20167 开云体育 Right now, I'm using the venerable 7805 linear regulator with a small heatsink to power my QLG1 and Clock.? Together they draw about 100ma.? Doing this allows me to connect up to any 6 to 15 VDC power source I have.? I consider the regulator defense against transients and other poorly regulated wall warts that would destroy both gizmos. Now, I'm considering using one of , which is much more efficient than the 7805, i.e., no need for a heatsink.? Not really all that cheap but I'm using one in another application and I've not had any problems.? I will handle 1.5A load at 90+% efficiency. 73 Cliff k1iff toggle quoted message Show quoted text -----Original Message----- From: [email protected] [mailto:[email protected]] On Behalf Of V Zecchinelli Sent: Monday, January 01, 2018 9:47 AM To: [email protected] Subject: [QRPLabs] 5Vdc U3S Can anyone suggest a reliable/stable 5dc P/S for U3S? 73 N1VIN? Vince
Curt wb8yyy All Messages By This Member #20185 Gang First, proceed with care. Review the specified damage input voltage for the U3S, and measure your candidate supply to insure its well below. Second, being an RF device, avoid any dc to dc converter unless it is substantially filtered for RF use. The example referenced seems to be for pc use. An old linear transformer based walwart could work, but most are unregulated.? also beware its output voltage can be much higher than the printed value when under a light load. We don't want to fry the U3S when its not transmitting. A 5 volt regulator and some capacitors can be added outboard, the circuit on the regulator data sheet is a starting point. Some have bought a 5 volt linear supply by mail order, but I don't recall details. Measure the output voltage of any supply before plugging in your U3S. Curt

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