SMD aluminum Electrolytic capacitorAlso called chip capacitor, chip multilayer Ceramic capacitor, high-frequency cylindrical capacitor, chip ribbon capacitor, chip Electrolytic capacitor, chip tantalum Electrolytic capacitor, and chip trimming capacitor are commonly used. Widely used in circuit design, this article introduces some precautions for the use of chip capacitors.
Chip capacitors are also called patch capacitors. The commonly used ones are chip multilayer Ceramic capacitor, high-frequency cylindrical capacitors, chip ribbon capacitors, chip Electrolytic capacitor, chip tantalum Electrolytic capacitor, and chip trimming capacitors.
When using chip capacitors, attention should be paid to:
(1) The working voltage of the capacitor must be lower than the rated voltage and must not exceed the rated voltage for use. For example, when the working voltage is 12V, the optional rated voltage is 16-25V; When the working voltage is 5V, 6-10V can be selected; When the working voltage is 3.3V, 4-6V can be selected. In addition, the capacitance of a capacitor is also related to its withstand voltage value. For example, sheet tantalum capacitors have a withstand voltage of 4-50V, 0.1-4.7 μ F small capacity capacitors have a rated voltage of 50V, while those above 10pF and with a withstand voltage value higher than 25V are rarely seen. Therefore, attention should be paid when designing circuits.
(2) Chip capacitors can replace small voltages with high voltages. For example, a circuit requires a 10V 1UF capacitor, which can be replaced by a 16V 1UF capacitor.
(3) The accuracy and material category of capacitors should be reasonably selected. The accuracy of commercially available chip capacitors is 0.01 μ Below F, its accuracy can reach level J (± 5%); At 0.01 μ Above F, there are fewer J grades, with K grades (± lO%) being the majority; At 0.1 μ If F or above, M level (± 20%) is the main factor.
(4) The capacity specifications (series) for chip capacitors with size code 0805 on the market are the most complete, while some capacities of 0603 may be out of stock. When the production batch is not too large, in order to prevent market shortages from affecting production, the welding pad can be slightly extended to make it suitable for 0603 and 0805, to avoid production stoppage due to missing parts.
(5) The chip multilayer Ceramic capacitor are rolled, and the model is on the tape reel, but there is no mark on the capacitors. Although its capacity can be determined by measurement methods, it is difficult to distinguish the accuracy level of material categories. Therefore, care must be taken during use, especially during manual assembly.
(6) Open type chip trimming capacitors cannot be soldered with wave soldering, while closed type chip trimming capacitors can be soldered with wave soldering.
(7) Sheet capacitors generally adopt a multi-layer structure, and some people use soldering iron for manual welding. At this time, it is necessary to pay attention to the welding speed to avoid overheating, which may cause the base end to break due to large temperature differences, resulting in a decrease in capacity.
(8) Chip capacitors use ceramic substrates, which are thin and brittle. Some circuit boards are relatively thin and may deform due to uneven force during installation, which can easily cause capacitors to break. Solution: In addition to improving the design process, tubular capacitors can also be used in areas that are prone to breakage, as they have high strength and are not easily damaged.
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