Ramping capacitor – possible problem
Yesterday i was building some tDCS with LM334 and try for first time use ramping capacitor. When i test device with load (5KOhms) all was ok ramping when i turn device on and ramping down when off. But when i change load (5kOhms potentiometer) during stimulation (testing) it create current peak up to 5 mA. I test it with few different capacitor and behavior is always the same (only different value of peak and the time to return to normal ). Device without capacitor work without problem. In result of this i use instead of capacitor serial load ( linear potentiometer 100kOhms ) allows me to do manual ramping (0,07mA to setup current).
My question is can anybody test this capacitor problem maybe i do something wrong, bad multimeter etc.. . If this problem is real, it’s a very bad idea to use capacitor for ramping in use the resistance change is not too quick but still can cause pretty high current peaks.
Well-balanced and chock full of relevant links. Check out the full article.
Almost every expert who talks about tDCS will tell you, “Don’t try this at home.” But a lot of people are starting to do just that. And it’s no wonder, given the parade of amazing results that researchers have reported achieving on subjects in the lab. It seems like you can make people better at just about anything if you just put the electrodes in the right place. To name just a few of the findings:
Applying the electrodes to the prefrontal cortex can improve learning and increase your working memory.
Applying them to the motor cortex can raise your threshold for pain and make you more adept with your nondominant hand.
Position them above the posterior portion of the left perisylvian area (in right-handed people) and they can facilitate language acquisition.
Stimulation of the parietal cortex can improve numerical reasoning.
Unfortunately, the quality of these videos is quite poor (always use a tripod, always get a direct audio feed of the lecture 😉 You can download an enhanced audio-only mp3 of the lecture here.
Prof. Marom Bikson of the Department of Biomedical Engineering at The City College of New York lecture on March 13, 2013 at the: Symposium at the the 10th Göttingen Meeting of the German Neuroscience Society.
“Non-invasive brain stimulation: mechanisms, effects and opportunities” introduces fundamentals of tDCS mechanisms and dose including how to achieve targeting using brain stimulation.
Continue the discussion here or on the lab http://neuralengr.com/forums/ or Soterix forums http://soterixmedical.com/community/
Prof. Marom Bikson “Using Computational Models in tDCS Dose” at 5th International Conference on Non-Invasive Brain Stimulation 2013 in Leipzig German (March 19, 2013). High-resolution slides available here (pdf).