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Replacing the 7805 on the Raduino so something that does not get so hot

K2BAG
 

Hi All,

My Raduino 7805 was getting hot not surprising as it was dropping 13.8 v down to 5V the difference is mostly turning to heat,  not good if you are running  portable on batteries, I remembered a  tip I heard on http://hamradio360.com/index.php/workbench/   podcast and that there was a drop in replacement for the 7805 that was switching based and is 90% efficient, I ordered two ($4.30 each)  from digikey, here is the link https://goo.gl/2uPHnz  and  replaced the 7805 on the Raduino it is pin compatible, it works well with no heat, I have so much QRM in Brooklyn that I can not tell if it is adding switching qrm, on a dummy load i don't hear anything.


(Having so much BITX fun thank you Farhan)

73 K2BAG

 

Michael Hagen
 

Hi,

I would try a resistor in series to the 7805, I have used really small and cheap ones from Mouser.  Usually 1 watt, they are like 0.4" long and $0.10.

Up the resistance until the voltage at the 7805 meets requirements.  Probably 8V will be enough.  Or put a 7809 in front?

The other thing, put a TO220 big regulator on it.  Also, if you have an LCD with back light, connect it to 12V thru a bigger resistor to take

the current out of the small regulator.  That is usually 50 ma or so.  You could maybe add a second regulator just for the LED back light, it is current you are setting, not voltage.

The switching version my not be good in a radio!  May have some nice birdies!

I never use the regulator built into Nano Arduinos, it is so cheap to put a TO-220 one external?

I have blow up the ones on the Nanos,  Nano is my favorite, I have used several of them in projects. eBay for a few bucks.


73s

Mike, WA6ISP

Ashhar Farhan
 

The switching mode regulators are invariably noisy. that's the main reason to avoid them.

MVS Sarma had a suggestion, we can remove the backlight LED out of the regulator and directly feed it with a resistor from 12v. that should significantly bring down the power consumption from the 7805

- f

On Sat, Mar 11, 2017 at 9:59 PM, <motdog@...> wrote:

Hi,

I would try a resistor in series to the 7805, I have used really small and cheap ones from Mouser.  Usually 1 watt, they are like 0.4" long and $0.10.

Up the resistance until the voltage at the 7805 meets requirements.  Probably 8V will be enough.  Or put a 7809 in front?

The other thing, put a TO220 big regulator on it.  Also, if you have an LCD with back light, connect it to 12V thru a bigger resistor to take

the current out of the small regulator.  That is usually 50 ma or so.  You could maybe add a second regulator just for the LED back light, it is current you are setting, not voltage.

The switching version my not be good in a radio!  May have some nice birdies!

I never use the regulator built into Nano Arduinos, it is so cheap to put a TO-220 one external?

I have blow up the ones on the Nanos,  Nano is my favorite, I have used several of them in projects. eBay for a few bucks.


73s

Mike, WA6ISP


Steve Barlow <swbarlow55@...>
 

Ash hat
Sorry to but it but I need some info
Myself and others have received bitx40 with the blink programme in the Arduino
Now I am a novice with this device and I have been told to just load the Bitx 40 sketch and all will be fine
But it is not
I am going wrong somehow
Can someone give me the exact process and files to get this thing working
It has now been going on for 6 days and I am no nearer
I am busting a gut to get on air with the radio so as you can imagine it is very frustrating
Would be grateful for any assistance
Thanks
Steve

On Sat, 11 Mar 2017 at 19:55, Ashhar Farhan <farhanbox@...> wrote:
The switching mode regulators are invariably noisy. that's the main reason to avoid them.

MVS Sarma had a suggestion, we can remove the backlight LED out of the regulator and directly feed it with a resistor from 12v. that should significantly bring down the power consumption from the 7805

- f

On Sat, Mar 11, 2017 at 9:59 PM, <motdog@...> wrote:

Hi,

I would try a resistor in series to the 7805, I have used really small and cheap ones from Mouser.  Usually 1 watt, they are like 0.4" long and $0.10.

Up the resistance until the voltage at the 7805 meets requirements.  Probably 8V will be enough.  Or put a 7809 in front?

The other thing, put a TO220 big regulator on it.  Also, if you have an LCD with back light, connect it to 12V thru a bigger resistor to take

the current out of the small regulator.  That is usually 50 ma or so.  You could maybe add a second regulator just for the LED back light, it is current you are setting, not voltage.

The switching version my not be good in a radio!  May have some nice birdies!

I never use the regulator built into Nano Arduinos, it is so cheap to put a TO-220 one external?

I have blow up the ones on the Nanos,  Nano is my favorite, I have used several of them in projects. eBay for a few bucks.


73s

Mike, WA6ISP


Jerry Gaffke
 

Good luck.

On Sat, Mar 11, 2017 at 12:20 pm, Steve Barlow wrote:

Ash hat

 

Allard PE1NWL
 

Steve,
please read Jerry's reply to the same question you posted in another thread:
https://groups.io/g/BITX20/message/23228?p=Created,,,20,1,0,0
It explains pretty well how you can get it working.
Good luck, 73 Allard PE1NWL

Master Ice <special@...>
 


I have to disagree there .
I use a 12V/5V buck/boost converter in my BITX and in other builds of mine.
As long as you follow sensible construction and wiring practices and layout, I have had no noise problems whatsoever.
 
Slim
----- Original Message -----
Sent: Saturday, March 11, 2017 7:54 PM
Subject: Re: [BITX20] Replacing the 7805 on the Raduino so something that does not get so hot

The switching mode regulators are invariably noisy. that's the main reason to avoid them.

MVS Sarma had a suggestion, we can remove the backlight LED out of the regulator and directly feed it with a resistor from 12v. that should significantly bring down the power consumption from the 7805

- f

On Sat, Mar 11, 2017 at 9:59 PM, <motdog@...> wrote:

Hi,

I would try a resistor in series to the 7805, I have used really small and cheap ones from Mouser.  Usually 1 watt, they are like 0.4" long and $0.10.

Up the resistance until the voltage at the 7805 meets requirements.  Probably 8V will be enough.  Or put a 7809 in front?

The other thing, put a TO220 big regulator on it.  Also, if you have an LCD with back light, connect it to 12V thru a bigger resistor to take

the current out of the small regulator.  That is usually 50 ma or so.  You could maybe add a second regulator just for the LED back light, it is current you are setting, not voltage.

The switching version my not be good in a radio!  May have some nice birdies!

I never use the regulator built into Nano Arduinos, it is so cheap to put a TO-220 one external?

I have blow up the ones on the Nanos,  Nano is my favorite, I have used several of them in projects. eBay for a few bucks.


73s

Mike, WA6ISP



Virus-free. www.avast.com

Michael Hagen
 

You are asking for help on something with a completely different subject?

Here is a link to programming document.

https://groups.io/g/BITX20/message/22618


There is a PDF file, save it so you can find it again.  It is hard to find in these posts.

I saw it yesterday, and still had problems finding it.

Keep Truckin!

73s

Mike, WA6ISP