Is it better to buy a bench PSU, or build one?

  • Thread starter theycallmevirgo
  • Start date
  • Tags
    Build
In summary, Building a PSU is one of the few "academic" projects I'm willing to consider. I don't see it taking me too long, and I can probably make something nice to look at. However, I may consider buying one at the $300-$500 pricepoint if I'm convinced that there are major advantages. Thoughts?
  • #1
theycallmevirgo
109
25
TL;DR Summary
Are there any advantages to a commercial PSU over anything I can build from online plans?
Building a PSU is one of the few "academic" projects I'm willing to consider. I don't see it taking me too long, and I can probably make something nice to look at. However, I may consider buying one at the $300-$500 pricepoint if I'm convinced that there are major advantages. Thoughts?
 
Engineering news on Phys.org
  • #2
Do you need a PSU ?
What would you use it for ?
 
  • Like
Likes russ_watters
  • #3
Baluncore said:
Do you need a PSU ?
What would you use it for ?
Entry level experiments/repair and electroplating.
 
  • #4
theycallmevirgo said:
Summary:: Are there any advantages to a commercial PSU over anything I can build from online plans?
Since this would be an AC Mains based project, one of the primary issues is safety (shock and fire). When you buy a commercial PSU, it comes with a UL mark or similar showing that it has passed the industry standard safety regulations and inspections by the safety agency. That can be important if your setup causes a fire or gets somebody shocked down the road.

Having said that, I built my first hobby PSU while I was working a summer job at Tektronix in their R&D Lab. I had great Mentors there who patiently explained the UL safety regulations and the reasoning behind them, and checked my work as I went (this was all on my own time outside of my regular summer job there). In the end I used that PSU for probably 20 years on all kinds of hobby projects and some consulting work, and it only got a little unreliable in the end because I'd used an inexpensive slide switch to control the +/-Vout section of the PSU (I think it switched between +/-15V and +/-12V, IIRC).

So if you have good in-person Mentoring by somebody who has actually taken AC Mains projects through safety approvals, then it may be a good learning exercise to build your own. You could also have the Mentor look over the "online plans" that you've found to help you pick the best one for your projected needs.

Another thing to consider is Radiated and Conducted EMI regulations (typically by the FCC in the US). When you buy a PSU, it has also gone through that testing to be sure that it will not cause interference with other devices nearby, and will not blow up if you key up a radio nearby (don't ask me why I know about that part). If you build a design that you find somewhere on the Internet, you will not have done that testing. So if there is some issue (like stability and RF parasitic oscillations in the SMPS section), you could get a knock at your door someday from the local radio tracking folks...

https://www.physicsforums.com/threads/this-is-why-em-interference-can-be-an-issue.993976/
 
  • Like
  • Love
Likes dlgoff, atyy, alan123hk and 2 others
  • #5
No question here. Buy a used one (eBay, swap meets, ham clubs, etc.). Since you are considering building your own, then you should be able to repair it if there's something wrong. In my experience, there is seldom anything wrong with PSs from eBay.

Don't discount the amount of money and effort that goes into the mechanical construction of these things. Even if you really want to design your own, buy a used one for all of the stuff you don't want to design and then replace whatever you think is fun or educational. You'll also learn a lot in the process by seeing the engineering choices that a pro made when they were designing a PS that had to be sold to make money; you'll be way more likely to make a safe and EMC compliant PS; and you'll end up with a better instrument on your bench when you move on to other projects.
 
  • Like
Likes theycallmevirgo, russ_watters and anorlunda
  • #6
berkeman said:
it may be a good learning exercise to build your own.

My point is simply, can I build anything that will exceed either specs or capabilities of anything I can buy for, say, $80? If so, what improvements can I make? If not, it's purely an academic exercise and I can't justify the time or money. I don't have any fundamental distaste for purely academic exercises, but right now is just not a good time.

Here's an example of a unit someone on another forum suggested. Can I do better?
 
  • #7
theycallmevirgo said:
However, I may consider buying one at the $300-$500 pricepoint if I'm convinced that there are major advantages. Thoughts?
[separate post]
My point is simply, can I build anything that will exceed either specs or capabilities of anything I can buy for, say, $80?
No.
 
  • Like
Likes berkeman, DaveE and theycallmevirgo
  • #8
theycallmevirgo said:
My point is simply, can I build anything that will exceed either specs or capabilities of anything I can buy for, say, $80?
No.
 
  • Like
Likes russ_watters
  • #9
theycallmevirgo said:
My point is simply, can I build anything that will exceed either specs or capabilities of anything I can buy for, say, $80? If so, what improvements can I make? If not, it's purely an academic exercise and I can't justify the time or money. I don't have any fundamental distaste for purely academic exercises, but right now is just not a good time.

Even if you have a superb technical and theoretical basis, and do not calculate the salary cost of your own work, every part you buy is a retail price, so there is little chance of achieving your desired goal.

On the other hand, It is the responsibility of the manufacturers to ensure that the parts supplied by the suppliers and its own final products meet the safety specifications, including sending the products to the laboratory for safety certification, and rigorous testing and supervision of the production process, etc. For the average person ,even if he has a certain understanding of the safety requirements and regulations, whether he can be able to achieve the same rigorous process and safety assurance when making his own will be questionable.

All in all, ensuring safety is paramount.
 
  • Like
Likes russ_watters and berkeman
  • #10
For $85, I'm tempted to buy one. No way would I consider trying to build a supply with the features the KD3005 has; 0.01 volt resolution, thermal protection, voltage and current overload and short-circuit protection plus you get test leads and a manual.

what improvements can I make?
What improvements do you think it needs? It's perfect the way it is.
 
  • Like
Likes jim mcnamara, russ_watters and berkeman

Related to Is it better to buy a bench PSU, or build one?

1. What are the advantages of buying a bench PSU instead of building one?

Buying a bench PSU offers convenience and saves time, as you do not have to source and assemble individual components. It also ensures a reliable and tested power supply, which may be difficult to achieve when building one from scratch.

2. What are the benefits of building a bench PSU instead of buying one?

Building a bench PSU allows for customization and flexibility, as you can choose the specific components and features that meet your needs. It also provides a deeper understanding of the inner workings of a power supply, which can be useful for troubleshooting and repairs.

3. Which option is more cost-effective?

The cost-effectiveness of buying or building a bench PSU depends on individual circumstances. Generally, buying a bench PSU may be more cost-effective for those who only need basic functionality, while building one may be more cost-effective for those who require specific features or higher power output.

4. Is it difficult to build a bench PSU?

Building a bench PSU can be challenging for those with limited electronics experience, as it involves soldering and understanding circuit diagrams. However, there are many DIY tutorials and kits available that can make the process easier for beginners.

5. Which option is more suitable for a beginner?

For beginners with little to no electronics experience, it may be more suitable to buy a bench PSU. This ensures a safe and reliable power supply without the need for technical knowledge. However, for those interested in learning and have some experience, building a bench PSU can be a rewarding and educational experience.

Similar threads

  • Electrical Engineering
4
Replies
136
Views
15K
Replies
2
Views
1K
Replies
7
Views
2K
  • Electrical Engineering
Replies
5
Views
4K
  • Electrical Engineering
Replies
3
Views
1K
Replies
7
Views
2K
  • Electrical Engineering
Replies
4
Views
1K
  • Computing and Technology
Replies
10
Views
6K
  • Astronomy and Astrophysics
Replies
24
Views
2K
  • Electrical Engineering
Replies
20
Views
8K
Back
Top