Views:1 Author:Site Editor Publish Time: 2021-02-01 Origin:Site
SMD capacitors are classified from other capacitors. SMD capacitors are also called multilayer (multilayer, laminated) chip ceramic capacitors, also called chip capacitors and chip capacitors. SMD capacitors are divided into: NPO capacitors, X7R capacitors, Z5U capacitors, and Y5V capacitors. SMD capacitors adopt simple packaging due to their small size, which can save a lot of resources, but the packaging difficulty is higher than other capacitors. Let's take a look at what other capacitors are and what are the functions of capacitors.
1. Aluminum electrolytic capacitors, the capacitance range is 0.1uF--22000uF, the best choice for high pulsating current, long life, and large capacity, widely used in power supply filtering, decoupling and other occasions.
2. Film capacitors, the maximum capacitance range is 0.1pF-10uF, with small tolerances, high capacity stability and extremely low piezoelectric effect, so it is the first choice for X, Y safety capacitors and EMI/EMC.
3. Tantalum capacitors, the capacitance range is 2.2uF-560uF, low equivalent series resistance (ESR), low equivalent series inductance (ESL). The pulsation absorption, transient response and noise suppression are better than aluminum electrolytic capacitors, which is an ideal choice for highly stable power supplies.
4. Ceramic capacitors, the capacitance range is 0.SpF-100uF, the crystallization of unique materials and thin film technology, which caters to the design concept of "lighter, thinner, and more energy-saving" today.
5. Super capacitor, the capacitance range is 0.022F-70F, extremely high capacitance, so it is also called "golden capacitor" or "farad capacitor". The main features are: ultra-high capacitance value, good charge/discharge characteristics, suitable for electric energy storage and power backup. The disadvantage is that the withstand voltage is lower and the operating temperature range is narrow.
The role of capacitors:
Coupling: The capacitor used in the coupling circuit is called the coupling capacitor. This type of capacitor circuit is widely used in the resistance-capacitance coupling amplifier and other capacitive combination circuits to block DC and AC. Filtering: The capacitor used in the filter circuit is called the filter capacitor. This capacitor circuit is used in power filter and various filter circuits. The filter capacitor removes the signal in a certain frequency band from the total signal.
Deconstruction: The capacitor used in the decoupling circuit is called the decoupling capacitor. This type of capacitor circuit is used in the DC voltage supply circuit of the multi-stage amplifier.
High-frequency vibration suppression: The capacitor used in the high-frequency vibration circuit is called the high-frequency vibration suppression capacitor. In the audio negative feedback amplifier, for the high frequency self-excitation that may occur due to the vibration, this capacitor circuit is used to eliminate the amplifier Possible high frequency howling.
Resonance: The capacitor used in the LC resonant circuit is called the resonant capacitor, and this capacitor circuit is required in both the LC parallel and series resonant circuits.
Bypass: The capacitor used in the bypass circuit is called the bypass capacitor. If you need to remove the signal of a certain frequency band from the signal in the circuit, you can use the bypass capacitor circuit. Depending on the frequency of the removed signal, there is a full frequency domain ( All AC signals) bypass capacitor circuit and high frequency bypass capacitor circuit.
Neutralization: The capacitor used in the neutralization circuit is called the neutralization capacitor. In radio high-frequency and intermediate-frequency amplifiers, and TV high-frequency amplifiers, this neutralizing capacitor circuit is used to eliminate self-excitation.
Timing: The capacitor used in the timing circuit is called the timing capacitor. A timing capacitor circuit is used in a circuit that requires time control through capacitor charging and discharging, and the capacitor plays a role in controlling the size of the time constant.
Integration: The capacitor used in the integration circuit is called the integration capacitance. In the synchronous separation circuit of the electric potential field scanning, using this integrating capacitor circuit, the vertical synchronization signal can be taken out from the field composite synchronization signal.
Differential: The capacitor used in the differential circuit is called the differential capacitance. In order to obtain the tip trigger signal in the trigger circuit, this differential capacitor circuit is used to obtain the tip pulse trigger signal from various (mainly rectangular pulse) signals.
Compensation: The capacitor used in the compensation circuit is called the compensation capacitor. In the bass compensation circuit of the deck, this low-frequency compensation capacitor circuit is used to enhance the low-frequency signal in the playback signal. In addition, there is a high-frequency compensation capacitor circuit. .
Bootstrap: The capacitor used in the bootstrap circuit is called the bootstrap capacitor. The commonly used OTL power amplifier output stage circuit uses this bootstrap capacitor circuit to increase the positive half-cycle amplitude of the signal by a small amount of positive feedback.
Frequency division: The capacitor in the frequency division circuit is called the frequency division capacitor. In the speaker frequency division circuit of the speaker, the frequency division capacitor circuit is used to make the tweeter work in the high frequency band, the mid frequency speaker works in the middle frequency band, and the low frequency speaker Work in the low frequency band.
Load capacitance: refers to the effective external capacitance that determines the resonant frequency of the load together with the quartz crystal resonator. Commonly used standard values of load capacitance are 16pF, 20pF, 30pF, 50pF and 100pF. The load capacitance can be adjusted appropriately according to the specific situation. Generally, the working frequency of the resonator can be adjusted to the nominal value through adjustment.
A capacitor is a ‘container of electricity’, a device that holds electrical charges. Capacitors are one of the most widely used electronic components in electronic equipment. They are widely used in circuits such as blocking, coupling, bypassing, filtering, tuning loops, energy conversion, and control. The advantage of chip capacitors over other capacitors is that they are small in size and have better temperature resistance and low capacity, which is why they are widely used.