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They're referring to microshock. If the patient has open sores, lacarations, or otherwise any small or large break in the skin, the smallest voltages on those openings can deliver a hazardous shock due to the human body's high conductance.
For that reason, the bioamplifiers need to have an extremely high input resistance; typically in the order of millions or billions of ohms. And the probes can't drop a voltage over a few microvolts. There was a good link to a company that specialized in these types of amps, and I'll post it up in a few minutes if I can find it.
They're referring to microshock. If the patient has open sores, lacarations, or otherwise any small or large break in the skin, the smallest voltages on those openings can deliver a hazardous shock due to the human body's high conductance.
For that reason, the bioamplifiers need to have an extremely high input resistance; typically in the order of millions or billions of ohms. And the probes can't drop a voltage over a few microvolts. There was a good link to a company that specialized in these types of amps, and I'll post it up in a few minutes if I can find it.
For the transducer schematic above, the output on Vo will swing from ~5 Volts to about 0.2 Volts (Q2's saturation voltage) as the beam moves in and out of view, so it's like a high-gain amp. (Although I think you should add a 1M0hm resistor between the base pin and ground)
Since the Q2 is either saturated or cutoff, you can add an edge triggered pulse counter to the output. But since the IR receiver is probably going to have a ton of hysterias, you would have to filter that HF noise out. But then again HF noise is always a problem for bio amplifiers (I think a solution was discussed in the previous link). The IR beam also -cough- has no carrier or filtering, so ambient lighting will affect it drastically.
I had one of those light thingys attached to my finger when I got my appendix out. They had it hooked up to a monitor, kinda like an osilliscope. When I would squeeze my finger really fast it would raise my pulse. I think I had it up to about 200 before I got yelled at.
I should have asked if I could keep it.
Light thingy = Transmittance probe for a pulse oximeter
Not only did it monitor your heart rate, but also your blood's oxygen saturation. They usually shine light through your finger to make the measurements.
JB
They're referring to microshock. If the patient has open sores, lacarations, or otherwise any small or large break in the skin, the smallest voltages on those openings can deliver a hazardous shock due to the human body's high conductance.
For that reason, the bioamplifiers need to have an extremely high input resistance; typically in the order of millions or billions of ohms. And the probes can't drop a voltage over a few microvolts. There was a good link to a company that specialized in these types of amps, and I'll post it up in a few minutes if I can find it.
the second ckt that has direct electrical contact with human body,and if not properly isolated , electric current(may be by accident) will flow to the i/p leads , and then , due to the special positioning of the electodes , the current will flow directly thru the heart , and that is fatal .
the first ckt shld work w/o this risk.
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