Unavailable 230VAC to 5V 1A Linear PSU?

Thread Starter

AlbertHall

Joined Jun 4, 2014
12,636
I need a linear 5V 1A PSU. The switch mode versions interfere with the radio receiver it is to power.
I have been unable to find such a thing.
Does anyone know of a suitable item?
 

SamR

Joined Mar 19, 2019
5,502
Not sure what form you want but there are plenty of 230V to 5VDC linear PSUs on AliX. Lowest I see are ~15W though unless you go for a wall wart.
 

crutschow

Joined Mar 14, 2008
38,561
Ebay has some listed for sale but, of course, it's caveat emptor buying from them.

If interested, building you own could be done with a 6Vac, 2A (transformer needs near 50% derating) or 12Vac center-tapped, 1A transformer, with rectifiers, filter capacitors, and an LM317 or LM7805 regulator on a heat-sink for a near "bullet-proof" supply.
 
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I need a linear 5V 1A PSU. The switch mode versions interfere with the radio receiver it is to power.
I have been unable to find such a thing.
Does anyone know of a suitable item?
This used to be a typical hobby project back in the 70s, mostly of the variable voltage kind. I have an ICOM IC-R75 receiver, bought it twenty five years ago. I have a large yard now, over an acre, so I can run long wires all over the place but to my extreme sadness all I can hear is noise and I think it's from the plethora if fixed mode supplies around my home, TVs, fridges, computers etc.

I'd love to get to the bottom of it all one day.
 

crutschow

Joined Mar 14, 2008
38,561
These are what I ordered
So I presume you will connect the the 4.5Vac transformer output windings in series to prove 9Vac to the 7805 module.
Note that will generate about 11.2V rectified and filtered DC to the 7805 so will generate about 6W dissipation of the 7805 for a 1A output.
That may make that small heatsink pretty hot.

But since the transformer is rated at 6VA, you likely can output more than about 0.5Adc without overheating the transformer.
Or did you buy the 12VA version?
 
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MrChips

Joined Oct 2, 2009
34,919
One of the first projects I built as a student.

1782669764419.png


1782670405486.png

transformer
bridge rectifier
LM7805
capacitors
power cord
strain relief
switch
fuse
LED
resistor
case
 

Thread Starter

AlbertHall

Joined Jun 4, 2014
12,636
So I presume you will connect the the 4.5Vac transformer output windings in series to prove 9Vac to the 7805 module.
Note that will generate about 11.2V rectified and filtered DC to the 7805 so will generate about 6W dissipation of the 7805 for a 1A output.
That may make that small heatsink pretty hot.

But since the transformer is rated at 6VA, you likely can output more than about 0.5Adc without overheating the transformer.
Or did you buy the 12VA version?
The rectifier will lose 2 diode drops from the rectified voltage and the 1 amp is an overestimate so I think it will be OK.
 
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