Identification of safety signs for low-voltage electrician exams

1. The prohibition sign is round, with a white background, a red rounded edge, a red slash in the middle, and a black image. Commonly used ones include "No Fireworks", "No Start", etc.

2. Warning signs are equilateral triangles with a yellow background and black edges and patterns. Commonly used ones include "beware of electric shock", "pay attention to safety", etc.

3. Command signs are round in shape, with a blue background and white patterns and text. The commonly used ones are "must wear safety helmet" and "must wear goggles".

4. Prompt signs are rectangular, with a green background and white patterns and text.