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Current limiting power supply recommendations #qmx #QMXplus

 

I am at the point where I will be installing the power boards. Might be time to get one. Can anyone recommend or not recommend one? I am in the U.S.
--
Wayne S.
KF7RCM
 

I just use a 9 volt transistor radio battery.
--
Tisha, AA4HA
 

An option you might consider.. Ron




On Wed, Sep 11, 2024 at 09:49 kf7rcm@... via <kf7rcm=[email protected]> wrote:
I am at the point where I will be installing the power boards. Might be time to get one. Can anyone recommend or not recommend one? I am in the U.S.
--
Wayne S.
KF7RCM
 

I use LM317 as current limited device.
 

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I like Ron's idea, but I'm more frugal.? I've had this particular unit more than two years, and it works.
It's surprising how often I find uses for it, once I had it.? Limiting current is useful sometimes.
?
-tim
N7TDB
 

> How have you found it to be with causing rfi/emi interference? I hear that is a common complaint with theses
(posting here so others can see)
?
Ron & I discussed this very question.? My radio sits two feet from this power supply, and I have not experienced any RF issues.
Of course, with Chinese manufacturing practices, it's possible they may have changed the design during the past two years.? Or not.
?
A data point of size one.? But I'm pretty happy with .
?
-tim
N7TDB
 

I use a buck-boost converter with a 12V LiFePO4 battery:
?

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$5.95 on Amazon

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This particular FULLY ASSEMBLED unit converts DC 5.5-30V input to 0.5-30V output 35W. ?All specs online. ?
It has two multi-turn pots - one for adjusting output voltage and the other for LIMITING current, if desired, and a nice backlit LCD display. ?
The display can be toggled for either input or output and shows both voltage and current. ?It also has an On/Off switch.

?

This unit fits nicely inside an Altoids tin mounted with foam double sticky backs that you can find at Lowe¡¯s, Home Depot and many other places. ?I notched my tin on both sides so that I use it with the lid closed. ?I have a Powerpole connector on the input line and a plug for my QCX Mini and QMXs on the output. ?This is very handy in the field.

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Derek WF4I

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OM Derek Brown WF4I et al,

I have just ordered this module suggested by OM Derek. I am in urgent need of a current limiting PSU. I love to maintain my equipment.
BTW is there any chance of getting the schematic of the 32 Volt DC 5.0 Amp Programmable Linear Power Supply by CIRCUIT SPECIALISTS?
Thank you all and kind regards,
73 de
Sudipta Ghose VU2UT


On Fri, Sep 13, 2024 at 8:34?AM Derek Brown via <dereksbrown=[email protected]> wrote:
I use a buck-boost converter with a 12V LiFePO4 battery:
?

?

$5.95 on Amazon

?

This particular FULLY ASSEMBLED unit converts DC 5.5-30V input to 0.5-30V output 35W.? All specs online. ?
It has two multi-turn pots - one for adjusting output voltage and the other for LIMITING current, if desired, and a nice backlit LCD display. ?
The display can be toggled for either input or output and shows both voltage and current.? It also has an On/Off switch.

?

This unit fits nicely inside an Altoids tin mounted with foam double sticky backs that you can find at Lowe¡¯s, Home Depot and many other places.? I notched my tin on both sides so that I use it with the lid closed.? I have a Powerpole connector on the input line and a plug for my QCX Mini and QMXs on the output.? This is very handy in the field.

?

Derek WF4I

?



--
One of those ... ...
 

Oh do come on guys! It is simple enough to make one, make an analogue one (with a transformer)


On Fri, 13 Sept 2024, 08:27 Sudipta Ghose VU2UT via , <oneghose=[email protected]> wrote:
OM Derek Brown WF4I et al,

I have just ordered this module suggested by OM Derek. I am in urgent need of a current limiting PSU. I love to maintain my equipment.
BTW is there any chance of getting the schematic of the 32 Volt DC 5.0 Amp Programmable Linear Power Supply by CIRCUIT SPECIALISTS?
Thank you all and kind regards,
73 de
Sudipta Ghose VU2UT

On Fri, Sep 13, 2024 at 8:34?AM Derek Brown via <dereksbrown=[email protected]> wrote:
I use a buck-boost converter with a 12V LiFePO4 battery:
?

?

$5.95 on Amazon

?

This particular FULLY ASSEMBLED unit converts DC 5.5-30V input to 0.5-30V output 35W.? All specs online. ?
It has two multi-turn pots - one for adjusting output voltage and the other for LIMITING current, if desired, and a nice backlit LCD display. ?
The display can be toggled for either input or output and shows both voltage and current.? It also has an On/Off switch.

?

This unit fits nicely inside an Altoids tin mounted with foam double sticky backs that you can find at Lowe¡¯s, Home Depot and many other places.? I notched my tin on both sides so that I use it with the lid closed.? I have a Powerpole connector on the input line and a plug for my QCX Mini and QMXs on the output.? This is very handy in the field.

?

Derek WF4I

?



--
One of those ... ...
 

I've had this linear bench supply for 7 years with adjustable voltage and current limit. It's what I use first for everything I build.
--
? 73
??? KD8CGH
 

I use this buck conversation unit. It's cheap and convenient. Add a thermister and computer heatsink/fan if used for extended periods.
Regards Darren G0OTT



On Fri, 13 Sep 2024, 10:16 Bob Benedict, KD8CGH via , <rkayakr=[email protected]> wrote:
I've had this linear bench supply for 7 years with adjustable voltage and current limit. It's what I use first for everything I build.
--
? 73
??? KD8CGH
 

On Thu, Sep 12, 2024 at 11:04 PM, Derek Brown wrote:
and the other for LIMITING current, if desired,
Be careful with that feature, many of those converters meter/limit current on the negative leg, and if something shunts that leg (grounded antenna or another converter) the metering/limiting will not be accurate.?
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I use them frequently, one just needs to be aware of their quirks.? I usually put a piece of black tape over the misleading current display.
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73, Don N2VGU
 

I use Talencell batteries, they put out 12v or less and have a on off switch, plus a USB port.
?
 

On Thu, Sep 12, 2024 at 01:31 PM, tim born wrote:
Of course, with Chinese manufacturing practices, it's possible they may have changed the design during the past two years.? Or not.
I have seen a lot of Chinese power supplies and the like with unpopulated positions for bypass capacitors at input and outputs.?
I suspect that if they were appropriately retrofitted many of the RFI issues would be resolved.? But they save a nickel leaving them out, likely AFTER passing EMI.RFI certification.
?
Kinda like Earl "Madman" Muntz used to do:
Muntz developed a television chassis that produced an acceptable monochrome picture with 17 tubes. He often carried a pair of wire clippers, and when he thought that one of his employees was "overengineering" a circuit, he would begin snipping components out until the picture or sound stopped working. At that point, he would tell the engineer "Well, I guess you have to put that last part back in" and walk away.
73, Don N2VGU
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