Hello Sir,
I am working on Electromyography (EMG) sensor development. There are three electrodes for recording electrical signal in the muscles. Two electrodes for creating voltage difference and third one is for reference electrode. Sensor reference electrode voltage is at 2.5 volts. The signal will swing between 0 to 5 volts with reference voltage 2.5v. Now, my question is that is it safe or not when i place 2.5v reference electrode on the body. if not, what are the precautions and is any muscle protection circuit for it. Secondly, what is the best approach for selecting muscle reference voltage.

Thanks for your time
Regards Hamas

 

Hi,
Any voltages that are safe to be connected to a person/body, should be from a low current (current limited) battery source, NOT through a mains transformer or adapter. Generally, EMG sensors are looking for a tiny amount of voltage changes and therefore they are very sensitive and work well with low current voltage sources such as a battery.
The reason an AC/DC power adapter should not be used is due to the fact that if anything fails within it, it can pass high voltages and currents to the body connected to it - that is not good and can easily be lethal.