Get in a product, many times, we do not have a circuit diagram, then we in this case, how about clear principles and the work of the board of it, which is to restore the kind of circuit diagram.
When in the face of some small objects, or when necessary, without drawing the face of electronic products, the need to draw the kind of circuit diagram, this is the kind of anti-formerly a circuit diagram. Although slightly larger scale situation becomes very complicated, but have the following points, I believe we can do, for the simple little circuit, it goes without saying.
1, choose a large volume, multi-pin and play a major role in the circuit components such as integrated circuits, transformers, transistors, etc. Figure painting reference member and the reference member selected from the start to draw the pin, can reduce errors.
2, if the PCB is marked with element numbers (eg VD870, R330, C466, etc.), since these numbers have specific rules, the same elements as the English alphabet after the first digit of the same functional unit, plus clever use should therefore draw . Correctly distinguish the same functional unit components, is the basis for drawing layout.
3, if the number of components on a printed circuit board not shown, for ease of analysis and proof-reading circuit, it is best to own part number. PCB manufacturers in the design of components arranged in order to make the shortest copper traces, usually the same functional unit components arranged in relatively concentrated. Once you find a unit plays a central role in the device, just follow it to find other elements of the same functional unit.