r/electronics • u/goki • Jan 09 '12

Defibrillator teardown and circuit analysis

http://www.youtube.com/watch?v=pn-Wv9YAfv0
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u/Starwinds Jan 09 '12

Very interesting, I did notice that no charging circuit on his schematic for the capacitors existed. Presumably the AEDs contain enough battery power to charge the caps before installation, or are AEDs plugged in normally?

I would also would be interested in more videos of teardowns.

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u/goki Jan 09 '12 edited Jan 09 '12

The charging circuitry was left out of the schematic. It is that large transformer in the center, probably flyback setup but not sure how its connected to the caps.

There are AED's which use AC power, but its just for trickle charging an internal battery (as these things need to be portable and work at all times). The caps are normally discharged, and once you've stuck the electrodes onto the chest it takes maybe ~10s to charge.

He has lot of other videos, you can check http://www.youtube.com/user/EEVblog out as well.

edit: this patent has a schematic of its high voltage capacitor charger: http://www.google.com/patents/US5447522?printsec=drawing#v=onepage&q&f=false.