Electronic Components Elecfans

With the continuous changes in the audio market demand, the audio amplifier design structure has made great progress. When selecting the best audio amplifier IC for a specific application, it is important to have a full understanding of the types of audio amplifiers available and their characteristics. The audio amplifier increases the amplitude of a small signal to a useful level while retaining the details of the small signal, which is called linearity. The better the linearity of the amplifier, the more true the output signal can represent the input signal. As the audio market's requirements for amplifier performance continue to change, audio amplifier circuit structures have made great progress. Therefore, the designer must understand the available audio amplifiers and their characteristics. This is the only way to ensure that the best audio amplifier is selected. In this article, we introduce the most important features of the various audio amplifiers available today: Class A,...

Reed relay , also called reed switch and reed switch, is composed of a pair of elastic reeds made of magnetic materials. The reeds are sealed in a glass tube filled with inert gas. The reeds overlap and there is a gap between them. The working principle of the reed relay When there is no magnetic field, the two reeds in the glass tube filled with inert gas are separated, otherwise, under the action of the magnetic field lines, the two reeds in the glass tube are magnetized to attract and contact each other, so that the two pins are connected to the circuit. When the external magnetic force is removed, the two reeds in the glass tube are separated again, and the connected circuit is disconnected. The characteristics of the reed relay High reliability; high safety; high adaptability; long life; compact structure; small size; superior electrical performance; high-speed operation; wide application. The solid-state relay has a non-contact switch with an isolation function. There is no mecha...

Spread spectrum communication has the advantages of anti-interference, anti-multipath, and low probability of interception. Since the 1970s, the theory and methods of spread spectrum communication have been greatly developed. Direct Sequence Spread Spectrum (Direct Spread Spectrum), as a common method of spread spectrum communication, has been successfully applied to military and civilian communications and has become one of the core technologies of the third-generation mobile communication system, fully demonstrating its significant advantages and strong vitality. Spread spectrum communication comes at the expense of increasing the bandwidth of information transmission. However, the existing frequency band resources are very limited. In order to increase the rate of information transmission within bandwidth per unit, the idea of ​​using direct sequence spread spectrum CDMA is proposed. At the sending end, one serial data information is converted into N parallel data information throug...

Software Radio, a systematic structure to realize wireless communication launched in recent years, is a significant breakthrough in the field of wireless communication in the wake of analog to digital communication, fixed to mobile communication. The basic principle of it is that the received analog signal is digitalized as soon as possible, and various functions of the radio are realized by software to the most extent. Software Radio is an open structure to realize all types of wireless communication systems through a general hardware platform and then through software loading. For Software Radio, the digitalized hardware platform is the basis, the programmable and reusable software is the core, and realizing multi-band,  multi-system, and universal reception is the goal. Figure 1 is the block diagram to realize Software Radio. Figure 1 shows the four-carrier communication system. The traditional simulation structure completes the conversion from RF(Radio Frequency) to IF(Intermed...

Although the force sensor has the characteristics of solidarity and durability, there are still some problems we should pay attention to when it is used.  1. protecting the force sensor from contamination caused by the external environment We should try to set up some "baffles" around the force sensor, and even cover the force sensor with a thin metal plate. This can prevent debris from contaminating the force sensor and certain movable parts, and this "contamination" often affects the weighing accuracy. 2. the connection of the shielding wire and the grounding point should be reasonable All wires leading to or from the display circuit should adopt shielding cables. The connection and grounding point of the shielded wire should be reasonable. If it is not grounded through the mechanical frame, it is grounded externally. 3. avoiding strong heat radiation The force sensor should use hinged copper wires (cross-sectional area of ​​about  50mm 2 ) to form an electrical b...

According to the current development status of infrared detectors, combined with the future development trend of thermoelectric cooler technology, the application of semiconductor coolers in infrared detectors mainly develops in the following aspects: 1.Lead-free solder During the rapid development of science and technology, lead solder is gradually being replaced by lead-free solder. In the actual application process of lead-free solder, it can effectively solve the heavy metal problem of lead in the application process of traditional leaded solder, and reduce the adverse impact on the ecological environment. In recent years, lead-free solders have gradually been used in the manufacture of semiconductor refrigerators, thereby reducing the adverse effects of semiconductor refrigerator manufacturing on the surrounding environment. It is consistent with the requirements of my country's sustainable development strategy. Lead-free solders are being produced, not only Can only be reduc...

The multi-axis wireless weighing sensor and digital technology have changed the force sensor.  About ten years ago, the force testing and force measuring industries were devoid of imagination. They developed a standardized way to formulate and simulate weighing sensors, torque sensors, and other devices, which worked for many years. However, with the development of technology, Big Data changed the work style of engineers and manufacturers. Therefore, this kind of ancient force measurement and simulation technology appeared to be so backward that it had no way to improve data collection or improve its efficiency. The digital revolution prompted the manufacturers of weighing sensors to deliberate from all aspects and think about how the clients developed products and how the factories and production lines worked. There are trends that some force measurement enterprises must follow, otherwise, they will face the risk of disappearance. Trend 1: multi-axis sensor The emergence of multi-...

 In order to ensure the set-top box is compatible with current TV sets, the set-top box must generate standardized VHF/UHF signals so as to drive the signals input by the TV antenna.  The universal RF modulator TDA8822 launched by Philip can generate standardized VHF/UHF TV channel signals which meet the PAL or NTSC standards across the world with a single-chip solution. The functions of TDA8822 include I 2 C bus which can fully control the picture carried frequency， sound subcarrier frequency, video modulation depth, subcarrier deviation, and picture-sound ratio. Moreover, TDA8822 allows the insertion of externally modulated subcarriers such as NICAM or PAL B/G two-channel/stereo signals. Because this chip is equipped with a subcarrier synthesizer that is fully adjusted and does not need to be adjusted， and a built-in phase-locked loop that can control the picture carrier, the only required peripheral equipment is the variable capacitance circuit suitable for its RF oscillat...