![]() The patient shouldn't be able to touch the electronics or the battery or whatever. You have to worry about electrostatic discharge: what it the patient rubs a balloon on their hair then touches the box? The circuit should have no exposed conductive surfaces that are connected to the electronics. IEC 60601 sometimes seems a little silly. Where's the second layer? I guess maybe you'd need two insulated boxes one inside another. Would the circuit's isolation conform to IEC 60601? If it were battery operated then that's one layer of isolation. I'm just telling you that you shouldn't do it. I've been using desktop PCs for decades and have never got a shock off one. (Domestic regulations are less stringent.)ĭid I operate it when plugged into a PC which was plugged into the mains? I'm not saying. leakage current, dielectric strength.Ĭan you operate it when it's plugged into a PC which is running on batteries? It wouldn't be allowed for a medical device but for a domestic device it probably would be allowed. A standard PC power supply almost certainly does not comply with the electrical IEC 60601-1 requirements from several standpoints, e.g. Your desktop PC is not electrically isolated to that degree therefore you should never operate the circuit when it's plugged into a PC which is plugged into the mains. What electrical isolation is required? An "Applied Part" has to be double isolated at 4000VAC. So the chip and its circuit is safe so long as it's battery operated. The chip operates at 3.3V so if the chip goes wrong, the maximum current is 3.3/180k = 18uA. The electrodes are connected to the chip through 180k resistors. The input impedance of the chip pins is 10Gohm so the "Normal Working" operation the current is under 1nA. When I examine the one I have, it appears to be one of the circuits in the "Application Circuits" section of the AD8232 datasheet. I don't know what circuit the manufacturer of the AD8232 module has used. ![]() This circuit would be classed as an "Applied Part". and in single fault condition it is 500uA a.c. How much current can I pass through the patient? In "Normal Working" operation the current limit is 100uA a.c.
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