Chip aluminum electrolytic capacitors commonly used are multi-layer ceramic capacitor, high-frequency cylindrical capacitor, flake polyester capacitor, sheet electrolytic capacitor, tantalum electrolytic capacitor, chip trimming capacitor and so on. It is widely used in circuit design. What precautions should be taken in the use of SMC.
The working voltage of the capacitor must be lower than the rated voltage and should not exceed the rated voltage. When the rated voltage is between 3V and 12V, the rated voltage is between 3V and 12V; for example, when the rated voltage is between 3V and 12V, the working voltage is between 3V and 12V; for example, the rated voltage is 6v-12v.
In addition, the capacitance of the capacitor is also related to the withstand voltage value. For example: sheet tantalum capacitor withstand voltage 4 ~ 50V, 0.1 ~ 4.7 μ f small capacity capacitor has rated voltage of 50V, but more than 10PF, withstand voltage value higher than 25V is rarely seen. Therefore, attention should be paid to the circuit design.
The chip capacitor can replace the small voltage with high voltage. For example: the circuit needs a 10V 1uF capacitor, which can be replaced by a 16V 1uF capacitor.
The accuracy and material type of capacitor should be selected reasonably. If the accuracy of the commercial chip capacitor is less than 0.01 μ F, the accuracy can reach class J (± 5%); if the accuracy is above 0.01 μ F, the accuracy of J class is less, and K class (± 10%) is the majority; if the accuracy is above 0.1 μ f, the accuracy is mainly of class m (± 20%).
The capacity specifications (Series) of chip capacitors with size code 0805 are the most complete on the market, while some capacities of 0603 may be out of stock. When the production batch is not too large, in order to prevent the market shortage from affecting the production, the pad can be extended slightly to make it suitable for 0603 and 0805, so as to avoid production stop due to lack of parts.
The multi-layer ceramic capacitors are all packaged in coils, and the model is on the reel, but there is no mark on the capacitor. Although its capacity can be known by measurement, it is difficult to distinguish the accuracy level of material category. Therefore, in the process of use, especially manual assembly must be careful.
Wave soldering can't be used for open chip trimming capacitor, but wave soldering can be used for closed chip trimming capacitor.
The multi-layer structure is widely used in sheet capacitors. Some people use soldering iron for manual welding. At this time, attention must be paid to the welding speed to avoid overheating, resulting in the breakage of the base end due to large temperature difference, resulting in the reduction of capacity.