Modifica di Electromyography (sezione)

====Electrical Safety of Equipment====
A failure in a device powered by electricity that has direct galvanic contact with the patient's skin can pose a health risk, as a potentially dangerous current could flow through the subject, who typically cannot defend themselves.

This problem is usually non-existent in battery-powered low-voltage equipment (from 3 to 15 V), but it becomes important in mains-powered equipment. While absolute safety cannot be achieved in all possible cases, isolation between the circuits connected to the patient (low-voltage powered) and the remaining parts of the device is usually considered adequate. This can be achieved through magnetic coupling (isolation transformer) or optical coupling (optoisolator or photocoupler). The isolation transformer is generally the simplest method from a technical perspective, but it can also be the source of the most problems regarding recording fidelity. In both cases, isolating the patient from the rest of the circuit also minimizes induced 50 Hz noise.

The safety levels of sEMG equipment are regulated by specific harmonized standards at the European level, which are used to assess the quality of the instruments. A "minimum" level of safety must be present in the equipment according to various European directives. Only if this minimum level of safety is met can the equipment be marked with the CE (Conformité Européenne) mark, allowing its commercial circulation within all EU states.