Can 9V DC Be Lethal in Biomedical Experiments?

  • #1
Ephant
147
2
9V DC can kill. Did you hear the story of this person who tried using multimeter to test resistance of his skin. He tried to thin his skin then the current of the multimeter probe got bigger and stopped his heart and he got killed.

So in electrode works in the skin where it is prep by abrading it with gel, the equipment must have utmost galvanic isolation.

I'd like to inquire about the different kinds of galvanic isolation.

Some use Opto-isolator to isolate the serial or USB wires. But here the chassis is still not protected, is it?

Then you have the ISO122 where the input signal is transmitted digitally across a high-voltage differential capacitive barrier. Is this safer than just isolating the serial or USB using opto-isolator?

https://www.ti.com/lit/ds/symlink/i...49383&ref_url=https%3A%2F%2Fwww.google.com%2F

Can you also use opto-isolator to isolate the electrodes or only the ISO122, and can the ISO122 be used on the serial or USB? Does it use different chip depending on where you want to put the isolation circuit?

Also isn't there a general commercial single channel differential isolation module where you insert the 3 electrode wires (2 differential plus ground/reference/common) and it has outputs where the 3 can be connected to any bioamplifier unit? Is this possible? Perhaps the safest of all as backup to any existing isolator in the main equipment?
 
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  • #3
Medical body contact electrodes are critical.
Different levels of protection, isolation, and grounding, are needed in different situations.
 
  • #4
Baluncore said:
Medical body contact electrodes are critical.
Different levels of protection, isolation, and grounding, are needed in different situations.

Many galvanic protection uses protection between AC and DC and ground loops. But how about DC. Even if your bio-amplifier is just using battery. It can shock you if it gets to the input, isn't it. So what is the DC isolator commonly used? Those references are mostly to prevent AC and DC contact. But what if you are just using batteries. Remember even 9V DC can kill.
 
  • #5
Thread paused for Moderation...
 
  • #6
Ephant said:
Did you hear the story of this person
Ephant said:
Many galvanic protection uses protection between AC and DC and ground loops. But how about DC. Even if your bio-amplifier is just using battery. It can shock you if it gets to the input, isn't it. So what is the DC isolator commonly used? Those references are mostly to prevent AC and DC contact. But what if you are just using batteries. Remember even 9V DC can kill.
After further review (and looking over your previous threads), this thread will remain closed.

I am not comfortable with you trying to use PF for advice for your DIY biomedical experiments. You do not yet have the EE and biomedical instrumentation experience to do that safely and ethically, and PF is not the place for you to try to learn those skills. Please do not post about your DIY biomedical experiments here on PF again. Thank you.
 
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FAQ: Can 9V DC Be Lethal in Biomedical Experiments?

1. Can 9V DC cause harm to human tissues in biomedical experiments?

While 9V DC is generally considered low voltage, it can still cause harm if applied directly to sensitive tissues or through broken skin. The primary concern is not the voltage itself but the current that flows through the body, which can cause burns or other tissue damage.

2. Is it possible for 9V DC to cause a fatal electric shock?

Under normal circumstances, 9V DC is unlikely to cause a fatal electric shock because the human body's resistance is typically high enough to limit the current flow. However, if the current path includes vital organs such as the heart, or if the skin resistance is significantly reduced, there could be a risk of serious harm.

3. What safety precautions should be taken when using 9V DC in biomedical experiments?

To ensure safety, always use insulated equipment, avoid direct contact with the skin, especially if it's broken or wet, and never apply the voltage across the chest or near the heart. Additionally, use proper grounding techniques and limit the current to safe levels using resistors or other current-limiting devices.

4. Can 9V DC interfere with biomedical devices like pacemakers?

Yes, 9V DC can potentially interfere with biomedical devices such as pacemakers. Even low voltages can disrupt the normal operation of these sensitive devices, so it is critical to avoid exposing individuals with such implants to any external electrical sources.

5. Are there specific regulatory guidelines for using 9V DC in biomedical research?

Yes, there are regulatory guidelines and standards that must be followed when using electrical sources in biomedical research. These guidelines are designed to ensure the safety of both researchers and subjects. It is important to consult relevant regulations, such as those from the FDA or IEC, and institutional review boards (IRBs) before conducting any experiments involving electrical currents.

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