【 Weak current College 】 how to restore the PCB circuit chart】

1. Select the volume, PIN number and play a major role in the circuit of components such as IC, transformer, transistor and other painting map datum pieces
, And then select the baseline start for the PIN, you can reduce the error paint.
2. If the printed circuit board is marked with a symbol number (such as VD870, R330, C466, etc.), as these numbers have specific rules after the English alphabet
First Arabic numerals of the same components within the same functional unit, so the paint should be specially with use. Distinguish the same functional unit of the element for
Parts, is the basis for drawing the layout.
3. If the PCB on the ordinal number of the components, for ease of analysis and correction circuit, the best one gives the number of components. Manufacturing plant in
Design of printed circuit board arrangement components so that the shortest foil alignment, generally the same functional units of the relative concentration of components. Find a
Units play a central role in the device, as long as this allows you to find the same functional units of other components.
4. distinguish PCB's ground, power and signal cables. To the power circuit, for example, power transformer secondary received negative side rectifiers
As power cathode, and Earth are attached between General bulk filter capacitor, the capacitor shell have polarity signs. May also be obtained from the three-Terminal regulators cited
Feet to find out the power and ground wire. Factory in PCB wiring, in order to prevent the self-excited, anti-interference, general ground wire copper foil set the widest (high
-Frequency circuit is often have large grounding copper foil copper foil), power cable, signal cable copper foil the narrowest. In addition, in both analog and digital
Word circuit of electronic products, PCB often separated from their respective ground to form independent grounding network, this can also be used as identification of judgement
Basis.
5. in order to avoid too many components pin wiring makes the circuit wiring cross interspersed, resulting in the art of illustration messy, power and ground may
By using the terminal symbols for the callout and grounding. If the components are more, you can also separate the unit circuit, painted and then grouped together.
6. sketch, recommend using transparent tracing paper, multiple color pen will ground wire, power cable, signal cable, components, etc. According to the color category art
Out. Modify, gradually deepening colors, making the drawing intuitive smart so that analysis of the circuit.
7. be familiar with some basic cell circuit and composed form, such as the classic drawing rectifier bridge, voltage circuit and amplifier, digital integrated circuits
And so on. First direct the cell circuit, circuit diagrams drawn framework that would improve the efficiency of the paint.
8. draw a circuit diagram, should as much as possible to find a similar product of circuit diagrams for reference, will play a more effective role.