I am a student of Electrical Engineering and I am currently working on a biomedical device which stimulates a human arm through functional electrical stimulation technique. Now for instance, if short circuit occurs then,a large amount of current can flow thus, damaging the human arm. So, I want to make something like a breaker myself which will break the circuit right then. My output voltage is around 50 Volts and max output current is 230mAmps.

I considered using a fuse but the problem with a fuse is that it will allow the current flow through to arm atleast once before cutting off the connection. I want to make a limiting circuit that has a low foot print so that the device doesn't look too large. Could you please give me some suggestions? Any help will be appreciated. Thank you! :)


closed as too broad by PeterJ, nidhin, uint128_t, Peter Smith, Robherc KV5ROB Mar 13 '16 at 18:54

Please edit the question to limit it to a specific problem with enough detail to identify an adequate answer. Avoid asking multiple distinct questions at once. See the How to Ask page for help clarifying this question. If this question can be reworded to fit the rules in the help center, please edit the question.

  • \$\begingroup\$ Connecting the human body to dangerously high voltages is not something to play around with. Someone could get hurt. \$\endgroup\$ – fredrik.hjarner Mar 13 '16 at 17:16
  • \$\begingroup\$ Google constant current circuits. From my physiology knowlege (well, what I can rememver of it), the exact voltage is largely immaterial for E-Stim usage (so long as adequate penetration is achieved). A constant-current device (preferrably an adjustable one with 230mA Imax) would serve your stated intent very well, and could potentially be built into a single-IC platform for minimal form-factor. \$\endgroup\$ – Robherc KV5ROB Mar 13 '16 at 18:53

Seriously? You shouldn't be anywhere near this project if you have to ask basic medical electronics safety questions on the internet.

50 Volts and 230 Amps!? You've got to be kidding! You clearly have no idea what you are doing. Go home and learn some basics.

How about I only apply 40 V limited to 200 Amps to your arm and see if you like it? At 8 kW you should have a few seconds before the water in the arm starts boiling.

What you are asking is too absurd to take seriously.

  • \$\begingroup\$ It was a typing mistake. It's 230mAmps (Milli Amperes) \$\endgroup\$ – user3863537 Mar 13 '16 at 13:38
  • \$\begingroup\$ Sir, you don't need to be so rude. I am a student asking for some help, its okay if you don't want to help. \$\endgroup\$ – user3863537 Mar 13 '16 at 13:43
  • 2
    \$\begingroup\$ @user3863537 That is still far past lethal current. Olin's point is still valid: your asking of the question means that you should not be running current through the human body. \$\endgroup\$ – uint128_t Mar 13 '16 at 13:53

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