Re: [DIYbio] Re: A simple and cheap >100V DIY electrophoresis power supply

No you won't be fine.  You need to add 2 fuses and PTC at a minimum.  And even then it is about as good an idea as playing with EtBr in your kitchen, i.e. not a good idea at all.

## Jonathan Cline  ## jcline@ieee.org  ## Mobile: +1-805-617-0223  ########################    

On 7/4/13 9:33 AM, Josiah Zayner wrote:

So from what I am understanding from what everyone is saying (Thanks for the comments) is that if I cover the circuit in a box to allow a  ground and add in inductors to isolate it from the AC it should be fine?

Most all power supplies have the final DC output at > 100VDC and a couple hundred milliamps so that should not be an issue only with this device.

On Thu, Jul 4, 2013 at 11:06 AM, Jonathan Cline <jncline@gmail.com> wrote:

Do not build the suggested circuit which runs directly from AC wall jack.  The article should be taken off your blog in my opinion similarly to suggesting that people should use EtBr at home (which also should just not be done).


Search the archives for my description of a simple current-limited power supply for electrophoresis at 220V.  The description is as follows. Total cost about $22-$25 from components bought online, no electronics knowledge required, some soldering is required.   Uses a 120V AC to 12V DC cigarette lighter adapter, then a 60W, 12VDC to 220V AC automobile inverter (EU version, for 220VAC), an EU wall plug (to plug into the EU automobile inverter), a bridge rectifier, and a filtering capacitor.   That yields 220VDC, current limited to 1A.  

Don't forget that AC voltage is listed as RMS so the actual peaks are higher (1.4x).

It would be possible to put all this together on a custom circuit board, overall though not really worth the effort since the inverter uses a switching power supply internally which would require some tuning to get right.  It would be a good project for an undergrad EE as a class project though, for ex. in a Power Systems class.


## Jonathan Cline
## jcline@ieee.org
## Mobile: +1-805-617-0223
########################

--
-- You received this message because you are subscribed to the Google Groups DIYbio group. To post to this group, send email to diybio@googlegroups.com. To unsubscribe from this group, send email to diybio+unsubscribe@googlegroups.com. For more options, visit this group at https://groups.google.com/d/forum/diybio?hl=en
Learn more at www.diybio.org
---
You received this message because you are subscribed to a topic in the Google Groups "DIYbio" group.
To unsubscribe from this topic, visit https://groups.google.com/d/topic/diybio/uNiIyU4xsvA/unsubscribe.
To unsubscribe from this group and all its topics, send an email to diybio+unsubscribe@googlegroups.com.
To post to this group, send email to diybio@googlegroups.com.
Visit this group at http://groups.google.com/group/diybio.

To view this discussion on the web visit https://groups.google.com/d/msgid/diybio/cedfa505-2cc5-4f71-afd5-425186465f31%40googlegroups.com.

For more options, visit https://groups.google.com/groups/opt_out.