Laboratory power supplies

[giorgos]

As you know, power supply is one of the most important instruments in any lab. Older models was based in linear design (transformer, rectifier, regulation and adjustment circuit) that was a reliable reciept but with the disadvantage of low efficient rate. As years passed, switching mode power supplies appeared primary in consumer electronics, computers etc. having many advantages like efficient, light weight and small size. Our main disadvantage is output noise, something unusefull in laboratory power supplies. Some manufacturers like Hameg claims that in their models, they follow complex design , that combines linear and switching design in order to get only the advantages of any type. You think that is appliable? or you prefer linear or switching design?

Also allow me to make a suggestion. I think that it would be a good idea, to create a seperate section about power supplies in ITTSB forum, because power supplies is a major part of instruments.

[Kiriakos GR]

My vote goes to linear ones, much less heat and long term stability.
When I hear the word switching it comes in my mind blown capacitors and LCR meters.

I have assembly with my hands over thirty 3-30V power supply units, and many more stabilized ones.
Low Ripple and voltage & current limiters always was features of the 1000 EUR solutions with advanced electronics.

Yes I will have to admit that modern switching type PSU can offer too voltage & current limiters in their output, but they can not handle more than 1-3A.

By my opinion everything goes down to personal requirements, for example all my personal needs are well taken cared by my Kenwood PD35-10 ( 0-35V  0-10A).
It gets permanent cooled by a 120mm fan and works rock solid in my hands since 1995. 


 

[giorgos]

Ι prefer linear too, its also easier for anyone who wants to build by his own, a lab power supply ( as i had done already too), to choose a linear design.
I would like to thank you too , for adopting my idea, to create a seperate section in forum about power supplies.

[Kiriakos GR]

to build by his own,

Unfortunately even the oldies linear designs they do have a high complexity level regarding their circuitry for proper voltage stabilization / DC filtering / voltage & current limiters.
But in the case of DIY PSU the good part is that the up-come represents your full set of knowledge and experiences in electronics at the time that you will make one. 

My most powerful PSU even today is my DIY version at 3-30V / 30A,  I build it so to feed 4X MRF317 ( in my youth 1991) 

http://www.ittsb.eu/forum/index.php?topic=735.0