Science Buddies: "Ask an Expert"

I am doing the experiment of separating hydrogen and oxygen. I built a galvaxistat and it reads about 36 volts... I tried to wire the breadboard, with 10k resistor, but when I plug in the volt meter the voltage jumps around from 20 to 70 volts, I must have something miss wired. I copied the location of the wires on the bread board from a how to on this site but still can't get it right. Is there a example of where each wire should be connected on the breadboard?

Thanks for your help.

rubberball - I believe his experiment uses four 9V batteries connected in series. You should read about 38 volts with fresh batteries across the connected batteries. When you use the breadboard the voltage should never jump above 38 volts. Are you using the correct range on the meter? I've attached a simplified schematic of this project. A solderless breadboard is a convenient way to make connections between several components. Typically, there are several rows of contacts, and the contacts in each row or 'island' are connected. The 'islands' are isolated from each other giving you many tie points to make connections. Make sure you understand how your breadboard's contacts are arranged or you might be short circuiting parts of your experiment.

Rick Marz

So should I put everything on the same row?

rubberball - Most solderless breadboards are very similar, and once you understand how the rows and busses are connected, you will have few problems. If you don't have the original instructions for the breadboard, here is a link to an instructional slide show. It explains the board very well and you can probably understand how your board works. When in doubt, use your multimeter in the ohms or continuity scale to verify connections or isolation between the islands of connecting points.

http://www.wisc-online.com/objects/View ... ?ID=eng701

Rick Marz

Thanks so much. This really helped me figure out what I was doing wrong

http://m.youtube.com/#/watch?v=lqw6ask5 ... qw6ask5HK0