Among electronic components, capacitors are like a bright star, playing an indispensable role in many fields with their unique functions and wide range of applications. Today, MobikeChip will unveil the mystery of capacitors for you to find out exactly what it is used for.
Key role in power supply circuit
(A) Filtering and voltage stabilization
In the power supply circuits of various electronic devices, capacitors are the key components to ensure stable power supply. Power supply output DC is often mixed with some AC components, also known as ripple. These ripples, if not dealt with, will have a serious impact on the normal operation of electronic equipment, resulting in unstable performance, noise and even damage. Capacitors can effectively filter these ripples by virtue of their characteristic of storing and releasing charge.
When the power supply voltage increases, the capacitor will store the excess charge; when the voltage decreases, and then release the stored charge, so that the output voltage remains stable, as if the power supply is equipped with a “voltage regulator”, for the subsequent electronic components to provide a pure and stable DC power supply. For example, in the power adapter of the computer, large-capacity electrolytic capacitors are widely used in the filtering link to guarantee that the computer motherboard and other components can work under a stable voltage.
(B) Energy storage backup
Capacitors also have the function of energy storage, in some specific scenarios, can play a role as a backup power. In some of the need to instantly provide a large amount of energy in the equipment, such as the camera's flash circuit, the capacitor pre-storage of electrical energy, when the flash is triggered, can be in a very short period of time will be the release of stored energy, so that the flash flash instantaneous burst of intense light. In addition, in some of the power stability requirements of the equipment, such as the server's uninterruptible power supply (UPS) system, capacitors as energy storage components, in the moment of utility power interruptions, can provide a short but sufficient power support for the equipment to ensure that the equipment has enough time for data preservation and safe shutdown, to avoid data loss and damage to the equipment due to sudden power failure.
The marvelous application in the signal processing circuit
(A) Coupling transfer
In signal processing circuits, capacitors are often used as coupling elements for connecting different circuit modules to realize signal transmission. As the capacitor has the characteristics of “DC isolation, AC”, it can pass the AC signal output from the front-stage circuit to the rear-stage circuit smoothly, and at the same time prevent the passage of the DC component to avoid the DC operating point between the front and rear-stage circuits affect each other. For example, in the audio amplifier circuit, the input audio signal usually contains DC and AC components, through the capacitor coupling, only the AC part of the audio signal can enter the amplifier for amplification, while the DC component is blocked, to ensure the normal operation of the amplifier, so that we can hear a clear, pure sound.
(B) bypass filtering
Capacitor in the signal processing circuit also bears the important responsibility of bypass filtering. In some electronic components work, will produce high-frequency noise signals, these noises will interfere with normal signal transmission and processing. By connecting a suitable capacitor between the power supply pins of these components and ground, high-frequency noise signals can be bypassed to ground, thereby eliminating the impact of noise on the normal signal. For example, in the power supply circuit of a microprocessor, in order to prevent the high-frequency noise generated by the microprocessor itself from being transmitted to other circuits through the power lines, a ceramic capacitor is usually connected near its power supply pin to bypass the high-frequency noise and filter it, so as to safeguard the stable operation of the microprocessor and the accuracy of signal processing.
Central position in timing and oscillation circuits
(A) Timing control
Capacitors play a key timing role in many circuits that require precise time control. By combining a capacitor with a resistor to form an RC timing circuit and utilizing the charging and discharging characteristics of the capacitor, precise time control can be achieved. For example, in the timing circuit of an electronic alarm clock, different timing times can be set by adjusting the values of the resistor and capacitor. When the capacitor starts charging, the voltage at both ends of the capacitor gradually rises as time passes, and when the voltage reaches a certain threshold, the corresponding circuit action is triggered, realizing the timing reminder function of the alarm clock. This capacitor-based timing control is widely used in various electronic devices, such as timers, time-delay switches and so on.
(B) Oscillation generation
Capacitors are also one of the core components of the oscillation circuit, with other components such as inductors and other components to form a LC oscillation circuit or crystal oscillation circuit. In the LC oscillator circuit, capacitors and inductors are constantly exchanging energy between the capacitor stored electric field energy and the inductor stored magnetic field energy conversion, thus generating a periodic oscillation signal. This oscillating signal is widely used in communication equipment, radio transmitters and other fields to generate carrier signals of specific frequencies for signal modulation, transmission and reception. In the crystal oscillation circuit, capacitors and quartz crystals with the ability to produce extremely stable oscillation frequency, to provide high-precision clock signals for electronic equipment to ensure that the synchronous operation of various parts of the equipment, such as computer clock circuit is based on the principle of crystal oscillation work.
In the motor start and run in the role of assistance
(A) startup assistance
In single-phase AC motors, capacitors are used to assist the motor start. As the stator winding of single-phase AC motors produces a pulsating magnetic field, which cannot produce a starting torque, capacitors are needed to produce a secondary winding current with a certain phase difference from the main winding current, thus forming a rotating magnetic field, so that the motor can be started smoothly. For example, common electric fans, washing machines and other household appliances in the single-phase motor, are inseparable from the capacitor start-up assistance. By reasonably selecting the capacity and parameters of the capacitor, it can ensure that the motor obtains sufficient torque during starting and starts quickly and smoothly.
(B) Operation optimization
In addition to startup assistance, capacitors can also play a role in optimizing the performance of motor operation. In some of the larger power motors, by accessing the appropriate capacitors in the circuit of the motor, the power factor of the motor can be improved and the reactive power loss of the motor can be reduced, so as to improve the efficiency of the motor and the stability of operation. For example, in industrial production of large pumps, fans and other equipment used in the motor, through the installation of capacitors for power factor compensation, can effectively save electricity, reduce production costs, while extending the service life of the motor.
At MobikeChip, we understand the importance and diversity of capacitors in the electronic field, and we are committed to providing you with high-quality, high-performance capacitor products to meet your needs in different application scenarios. Whether you are engaged in R&D, production of electronic equipment, or equipment maintenance, electronic production, if you have any questions about capacitor selection, application or other related issues, please feel free to visit MobikeChip's website, and our professional team will be happy to serve you, and explore the infinite possibilities of the electronic world with you.
