Maybe explain why you're taking this personally.  What I see is a lack of simple homework.  Basically your page is suggesting something as unsafe as using a hair dryer while taking a bath in a bathtub  - common sense not to do it, right?   It's a free country, do what you like, I guess.

A good paper on this topic is:

Analytical Biochemistry, Volume 137, Issue 1, 15 February 1984, Pages 156-160, An economic “power supply” using a diode for agarose and polyacrylamide gel electrophoresis, Y. Kadokami, K. Takao and K. Saigo

Quoted is a quick discussion I found with simple web search in a couple mins from 1997 -- interesting that this article below has a similar opinion to mine, why might that be? --   "" These cheap, simple designs are hardly novel and certainly not even worth paying anyone to get a circuit diagram.  ... No one who has any knowledge of/respect for electricity would use a stupid, cheap, live output "power supply".  ""    I have a hard time believing you chose the bridge etc of your circuit but didn't run into any of the related information regarding why direct connection to AC without fuses is bad, so why did you chose to ignore it, is the better question, and now feel personally attacked by those pointing it's drawbacks?

Didn't find anything online?  How long did you look?  Did you look in the journal Electrophoresis?  What search terms did you use?  Ask your PI?   Ever wonder why you didn't find anyone else using such a "simple and cheap" circuit?    It's all been re-hashed before even on this list, which you could also search quite easily in the search bar or with a link like this one https://www.google.com/search?q=electrophoresis+power+diybio
 or here http://www.google.com/search?q=Open+Gel+Box+2.0+Power+Supply
 or here http://openwetware.org/wiki/Talk:DIYbio:Notebook/Open_Gel_Box_2.0/Power_Supply
 or here http://www.google.com/search?q=Simple+power+supply
 or here http://www.eleccircuit.com/transformerless-ac-to-dc-power-supply-circuits/
 or here http://www.electroschematics.com/3752/transformer-less-power-supply/
  note the disclaimer "Caution! Circuit is lethal since it carries high volt AC. Do not touch or test when connected to Mains. Enclose in a shock proof case."
but you wouldn't be enclosing it in a shock proof case, because that's impossible, as the gel box is part of the circuit and directly accessible.


I'll just quote the entire article below
 
--quote --

Simple power supply

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In article <5vub4d$d5v at cpca3.uea.ac.uk>, AndrewLeech at see.sig.for.email  (Andrew Leech) wrote:    > In article <5v74tp$qdi at news.cuny.edu>, kang at msvax.mssm.edu says...  > >  > >Dear colleagues;  > >  > >I recently developed new power supply which is totaly different from the  convent  > >ional one in that it does not use the core and coil and condenser for  transformi  > >ng AC to DC. Instead I used bridge diode just to change the AC to  directional pu  > >lse current.   >   > It's been done. We have a gel electrophoresis system called "Mupid-2", made  > by Cosmo Bio Co Ltd of Tokyo, Japan.  > Although the circuit diagram is not given in the manual, its characteristics  > are almost exactly the same as yours, and it does say "no transformer is  > used"...    And the Mupid is an extremely dangerous rig.  We have a Mupid (not a  Mupid-2) in the lab that I would never use and I have warned those who use  it that this design is nothing short of idiotic.  I just verified what I  already knew and that is that the negative output (in the case of the setup  we have, labelled 'BLK') is at full line voltage (here 115-120 AC) with  reference to any ground (in the UK, "earth") and that means air or gas  taps, sinks and faucets, and the metal cases of essentially any electrical  lab equipment which is grounded, in other words virtually everything sold  in the past 20 years in North America.  The current output of this "power  supply" would be more than enough to kill.    These cheap, simple designs are hardly novel and certainly not even worth  paying anyone to get a circuit diagram.  In 1964 the journal Ann. N. Y.  Acad. Sci. (vol. 121) devoted a whole issue to the then very young field of  polyacrylamide gel electrophoresis. In an article by Baruch J. Davis there  are presented two designs for power supplies, and one labelled "Simple 150  volt supply" is a circuit diagram obvious to anyone with any electronics  knowledge, a bridge rectifier (full wave) with a filter capacitor and a  couple of resistors on the line side of the diodes. It is called a 150  volt, 1 ampere power supply; 1000 mA should allow a fairly effective  electrocution.  Of course such cheap "power supplies" don't have any meters  because they are more expensive than transformers.    > >I made the beta version of this apparatus and wanat to sell with 40 dollars.  >   > You might want to check it hasn't been patented first.  >   > Then,  > In article <wqIErKAYO6F0Ewki at genesys.demon.co.uk>, duncan at genesys.demon.co.uk   > says...  > >  > >This would be 'illegal' in the UK/EEC due to lack of safety and would  > >not be allowed to be sold. If one of the rectifiers fails short circuit  > >you can get full mains AC on the output with lethal consequences.  With  > >no current limiting this would kill. Given that a transformer and  > >condenser are literally only a few dollars surely it makes sense to use  > >that route?    This type of design would never meet standards in either the US or Canada  nor I'm sure in any western European country.  Given that electrophoresis  setups are used with conductive water solutions and that there is  frequently liquid spilled around the gel setup (which can leak as well) and  you've got the makings of a disaster.  And don't be lulled into any false  sense of security that there must be a component failure to cause a  problem; even in a full wave rectifier the output is only one diode from  the input, and the voltage drop across a silicon diode is only about 1.5  volts.  What you get hit with is a pulsed DC rather than a true AC but that  will give you a nasty bite none the less.    Indeed the cost of a basic transformer is trivial, even a simple 120 volt  to 120 volt .5 amp isolation transformer. Be warned though that variable  autotransformers (in the US and Canada sold under the names Variac and  PowerStat) have one line as a straight feed through and thus are not fully  isolated.    > I wasn't in the lab when it arrived, so where it came from...? Anyway it  > is well fused and has a cutout switch in the gel tank to stop you frying  > yourself.    Fuses protect electronic circuits not humans; a 250/500 mA fuse is totally  irrelevant when you are the load on the circuit.    > Ironically though, because the mains supply in the UK is 230V, it has to  > be supplied from a small step-down transformer, so it is isolated.    So they sell this cheap setup with a stepdown transfomer for use in Europe  where the line voltages are 205-250?  That's brilliant marketing, having an  external transformer worth more than the standard power supply.    > Personally I don't like it - but that may be because the gel trays are  > rather small and fiddly for cutting out bands, and of course you only have  > "slow" and "fast".    No one who has any knowledge of/respect for electricity would use a stupid,  cheap, live output "power supply". What amazes me is that we don't hear  about lab personnel being killed by such treacherous setups.    Dave Spencer    --   David F. Spencer, PhD  Dept. Of Biochemistry  Dalhousie University  Halifax, Nova Scotia  Canada    dspencer at is.dal.ca  dspencer at rsu.biochem.dal.ca        -- end quote --    

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