Power supply restrictions are mainly reflected in the following three aspects:

1. Isolate the power electric and electronic components.

2. Take measures to prevent external interference electromagnetic fields from coupling to electronic components through relays or current outputs.

3. Limit the working power supply and voltage of the sensing circuit

Intrinsically safe circuits can be divided into two categories: ia and ib. The Ib intrinsic safety circuit must ensure that the circuit components do not explode during normal operation and when there is a fault in the system. The Ia intrinsic safety circuit requires that the components do not explode under normal working conditions and when there are two failures.