大象传媒

When you first see a circuit diagram it looks rather like a map with lines and symbols on it. In the nineteenth century, when scientists were first learning about electricity, the easiest way for them to describe what they were doing was to draw it. In 1878 Thomas Edison had come up with his latest invention which was the incandescent light bulb. His drawings were logical. When he drew a circuit the symbols he used looked much like the real things. But there was a problem. Not everyone used the same symbols in their circuit diagrams so they had to agree to the symbols used. Now builders, engineers and electricians can all understand the circuit diagrams.