Electronics > Beginners

DIY Variable power supply

<< < (4/4)

not1xor1:

--- Quote from: chiken on March 20, 2019, 07:30:35 pm ---Hello everyone, :)
Having Power supply with variable voltage and current would be quite hand to me as a student so i wouldnt fry things every so often,
and since my attempt to buy cheap Variable Psu has failed, and trying to fix chinese boards failed even more :horse: I decided that it would be best to build it myself.

--- End quote ---

you might buy those cheap linear Chinese PSUs...
You should find 0-30V 0-5A new units around 50 €.
Then you have to fix:
- the transformer (usually nuts and bolts lack locking washers and are lose)
- put a real heat sink (TME has a good and cheap one for 2 TO3 BJTs)
- change some electrolytic capacitor (those at the input filter are 50V unknown brand - you might use 2 samwha 4700µF 63V)
- change the rectifier bridge with a more beefy one (10A or more)
- optionally improve air flow
- do not use it continuously above 3-3.5A

eletronob:

--- Quote from: not1xor1 on March 24, 2019, 08:33:33 am ---- put a real heat sink (TME has a good and cheap one for 2 TO3 BJTs)
--- End quote ---
What is TME?

Shock:

--- Quote from: eletronob on March 29, 2019, 07:47:40 am ---
--- Quote from: not1xor1 on March 24, 2019, 08:33:33 am ---- put a real heat sink (TME has a good and cheap one for 2 TO3 BJTs)
--- End quote ---
What is TME?

--- End quote ---

Euro parts distributor https://www.tme.eu

Jwillis:

--- Quote from: chiken on March 20, 2019, 07:30:35 pm ---Hello everyone, :)
Having Power supply with variable voltage and current would be quite hand to me as a student so i wouldnt fry things every so often,
and since my attempt to buy cheap Variable Psu has failed, and trying to fix chinese boards failed even more :horse: I decided that it would be best to build it myself.

And since I did not reach that level of education to be able to make schematics that far myself, but am able to understand already made schematics,
Is there any fellow forum colleague who would share  some schematics of PSUs with variable voltage and constant current for educational purposes
I was thinking about 30V and 10A what would maybe be overkill, but that is pinnacle, 5A would be fine, but wouldnt go lower than that, Voltage 20V+...

And if anyone is wondering why would i give that much effort in it and simply not collect some money and buy one for 50$ from amazon, well few reasons why :
1. i like to make things myself  :-/O
2. as a student, budget is stingy..
3. as i said, ive already tried buying one, even though it was lot cheaper, but wouldnt risk buying chinese crap again
4. if i have to choose between buying something for 20$, and buying parts and making it myself for 20$ without thinking would choose 2nd option,
as i said im student and making it myself would vastly help me understand principles of it and maybe one day create one myself

If is there any other place that i could post like this, please let me know.

Critics somewhat allowed, just dont go berserker please hehe

--- End quote ---

Building your own is the best part of learning. Anyone can just go out and buy a power supply or a few pre-built circuit boards and connect them together but you learn nothing.The hardest part is finding something on the net that is tried and true and sifting trough the garbage to find something that really works .
Out of the ones that really work , its hard because  the lack of available parts or the shear complexity just makes them cost a fortune to put together.
These two  have fully adjustable voltage and current .One is based on the LM723 which is readily available and inexpensive.The other is base on the now obsolete MC1466L/MC1566L.The MC1466L can be built that uses common discrete s if you can't locate the chip. Or if you are really ambitious a circuit exists using SMD. Both circuits are fairly stable and inexpensive to build.Also theirs a lot of information available to help with many questions you may have.

Lm723 variable power supply https://www.airspringsoftware.com/p/1549767647173118/ or here http://www.classdaudio.tk/index.php?page=3010
I'm not familiar with this one but I'm sure you can get help on it if needed.

MC1466L/MC1566L variable power supply http://chemelec.com/Projects/MC1466/MC1466.htm or with the SMD version here https://hackaday.com/tag/mc1466/
Getting the MC1466L SMD boards is easy and I picked up 6 for about 14 dollars US found here https://oshpark.com/shared_projects/tU1Dv8o4
I built this one and it works great.The only problem that popped up was the voltage control potentiometer needs a small resistor between the wiper and ground instead of being directly tied to ground.

Hope this helps some.

Navigation

[0] Message Index

[*] Previous page

There was an error while thanking
Thanking...
Go to full version
Powered by SMFPacks Advanced Attachments Uploader Mod