
电容作为无源器件,经常被应用于各种电子电路中。其中,在电路中,电容经常被用作旁路和去耦两种功能,那么,旁路和去耦到底有什么不同?在实际应用中该如何进行区分其作用?设计时该如何进行选型?PCB设计时有哪些注意的地方呢?本文将针对以上问题进行讨论。 . a. Definition Bypass capacitor: Bypassing can be defined as the method of adding a path of low-impedance for shunting the transient energyto the ground which is the source. It is a requireme. . 通过以上的分析,我们不难发现,在使用中,二者之间并不存在太大的区别,其都具有将AC信号分流到GND的作用。而二者之间最明显的区别在于,旁路电容的设计是使其分离任何不期望的噪声信. [pdf]
The first line of defense against unwanted perturbations on the power supply is the bypass capacitor. A bypass capacitor eliminates voltage droops on the power supply by storing electric charge to be released when a voltage spike occurs.
Bypass Capacitors are generally applied at two locations on a circuit: one at the power supply and other at every active device (analog or digital IC). The bypass capacitor placed near the power supply eliminate voltage drops in power supply by storing charge and releasing them whenever necessary (usually, when a spike occurs).
Bypass capacitors are frequently needed in electronics development. Figure 1 shows a switching regulator that can generate a lower voltage from a high voltage. In this type of circuit, the bypass capacitor (C BYP) is especially important.
Coming to the bypass capacitor placed near VCC and GND pins of an IC will be able to instantaneous current demands of a switching circuit (digital ICs) as the parasitic resistance and inductance delay the instantaneous current delivery. How Bypass Capacitor Eliminates Power Supply Noise?
Hence, when selecting a capacitor for bypassing power supply from internal noise of the device (integrated circuit), a capacitor with low lead inductance must be selected. MLCC or Multilayer Ceramic Chip Capacitors are the preferred choice for bypassing power supply. The placement of a Bypass Capacitor is very simple.
Decoupling and bypass capacitors help stabilize power fluctuations on the PDN, ensuring consistent signal levels and maintaining a steady voltage at an IC’s power and ground pins. To assist with effective usage, we've outlined essential design guidelines for bypassing and decoupling capacitors in your next PCB.

Class-X and Class-Y capacitors are safety-certified and generally designed and used in AC line filtering in many electronic device applications. These safety capacitors are also known by other names, including EMI/RFI suppression capacitors and AC line filter safety capacitors. (EMI stands for electromagnetic interference. . Class-X and Class-Y capacitors are classified according to: 1. their peak voltage/rated voltage and 2. the peak impulse voltage that they can safely withstand. Tables 1 and 2. . Subclass X2 and Y2 are the most commonly used safety-certified capacitors. Depending upon your own application and requirements, they are. . Because Class-X and Class-Y capacitors must be connected directly to AC lines (line-to-neutral or line-to-ground) in order for them to perform their EMI and RFI filtering functions, they must be rated and certified as "safety. . All safety-certified capacitors should have the proper logo markings/symbols on their casing. See Figure 4 below for an example and see Figure 5 for a definition/description of these logos: [pdf]

Power capacitors are electrical energy storage devices, thus you must always handle them with caution. Even if they are turned off for a long period of time, capacitors might still be charged with high voltage, and this may be lethal. For this reason, please be extremely careful when handling capacitors and electrically. . The most frequent risk factors which cause capacitor damage and possible failure of the internal protective devices are: 1. Exceeding the. . Never use capacitors that have dents of more than 1 mm depth or any other mechanical damage. This applies also in cases of leakage. To ensure the functionality of the overpressure disconnector, do not. . The capacitor manufacturer cannot predict every possible stress which a power capacitor may be subjected to, and which has to be taken into account in a proper design. This means that the user bears crucial co-responsibility.. [pdf]
The shelf life of most capacitors depends on environment factors such as humidity, temperature, and atmospheric pressure. Subjecting capacitors to harsh conditions can significantly affect their electrical properties, or even damage them completely.
Ceramic capacitors should be stored at temperature and humidity conditions specified by the manufacturer. Before using a capacitor, you should check the recommended shelf life, date of receipt, and inspect terminations. For most capacitors, the shelf life is significantly determined by storage conditions.
( 2 ) Operating temperature and applied ripple current shall be within the specification. qThe capacitor shall not be used in an ambient temperature which exceeds the operating temperature specified in the specification. wDo not apply excessive current which exceeds the allowable ripple current.
The electrical characteristics that are affected when these capacitors are stored for a long time without charge are equivalent series resistance (ESR), leakage current, and capacitance. ESR and leakage current increase while capacitance decreases. Nevertheless, the changes are small if these capacitors are stored at room temperature.
Before using a capacitor, it is important to check its receipt time. Some capacitors require reforming after they have been stored for an extended period of time without recharge. To maximize the life of capacitors, they should be stored under conditions specified by the manufacturer.
Subjecting capacitors to harsh conditions can significantly affect their electrical properties, or even damage them completely. The effect of environmental factors on the shelf life of capacitors varies depending on the chemical composition and construction of a capacitor.
Committed to delivering cutting-edge energy storage technologies,
our specialists guide you from initial planning through final implementation, ensuring superior products and customized service every step of the way.