The circuit board serves to carry various components and connects these components organically with copper foil. It is the basis of the entire circuit.
The number of copper foil surfaces on a circuit board can be divided into single-plane and double-plane, multi-layer boards.
Single panel features: Single panel has only one side with copper foil, components are mounted on the other side of the opposite side of the copper foil, due to the low strength of single panel adhesion, so the temperature during manual soldering can not be too high, the temperature is generally 360 ° + -30 °, time can not be too long, usually in 2-3 seconds, long welding time will cause the copper peel off and damage.
Dual-panel features: Both sides of the double-sided panel have copper foil, which means that the components are mounted on one side and there is also copper foil. The double-sided board is used to connect the copper foil on both sides of the hole called the via (the production line often feedbacks the vias). .
Circuit board soldering process requirements: bright and smooth solder joints, oval-shaped, tin and welded objects are solid fusion, reliable connection, and moderate amount of tin, up to no more than pad edge, at least not less than 80% of the pad area , Tin on all sides of the pin is good, there is no tin hole, short circuit, false welding and other defects.
Bonding circuit board process requirements: circuit board surface must be clean, no oil, no oxidation, no dust, and other factors that affect the welding in the inside. Help the gold finger line width 0.2MM
Patch production process: brush paste - paste components - over reflow - inspection appearance. (It should be noted that components should not be misplaced and cannot be attached)
Understanding of electronic components: The general electronic components are resistance, capacitance, diode, triode, inductance and so on.
The role of resistance: resistance and partial pressure. The sign of the resistor is denoted by "R". The unit is "Ω" and the symbol of the figure is "".
The role of the capacitor is: store charge, pass AC, DC blocking and filtering. Capacitors can be divided into polar and non-polarized capacitors. Use of polar capacitors should pay attention to the difference between the positive and negative leads. The circuit symbol is denoted by “C”. The unit is “Fara”, or “F” for short. Units are UF, NF, PF. The graphic symbol "" or "" indicates.
Diode: The role of the diode is: regulation, rectification. The symbol of the diode in the circuit is denoted by “D”, the symbol “ ” or “ ” indicates that the symbol of the voltage regulator is “ ”, the diode is polar, and the direction cannot be used wrongly.
The role of the transistor: amplification, switching. There are several ways to represent the transistor in the PCB. They are "Q" or "T".
The role of the inductor: DC blocking, separated by AC. The unit of inductance is "Henry" or "Hen" for the letter "H", and the inductor is represented by the letter "L" in the circuit.