Meet the Highly Reliable Electrolytic Capacitor, the Tantalum Capacitor

       The electrolytic capacitor is a type of capacitor that uses an electrolyte, an ionic conducting liquid, as one of its plates, to achieve a larger capacitance per unit volume than other types. They are often referred to in electronics usage simply as "electrolytics". They are used in relatively high-current and low-frequency electrical circuits, particularly in power supply filters, where they store charge needed to moderate output voltage and current fluctuations in rectifier output. There are two types of electrolytics; aluminum and tantalum. The tantalum capacitor is a highly reliable type of electrolytic capacitor, which is available in both solid-bodied and separately encased forms. The encased "wet" variant is not used often in modern designs. Surface mount tantalum capacitors are widely used in circuit designs because of their volumetric efficiency, basic reliability and process compatibility.

    The low leakage and high capacity of tantalum capacitor favors their use in sample and hold circuits to achieve long hold duration, and some long duration timing circuits where precise timing is not critical. They are also often used for power supply rail decoupling in parallel with film or ceramic capacitors which provide low ESR and low reactance at high frequency. Compared to aluminum electrolytics, tantalum capacitors have very stable capacitance, little DC leakage, and very low impedance at high frequencies. However, unlike aluminum electrolytics, they are intolerant of positive or negative voltage spikes and are destroyed (often exploding violently) if connected in the circuit backwards or exposed to spikes above their voltage rating.

    Moreover, tantalum capacitors are more expensive than aluminum-based capacitors and generally only available in low-voltage versions, but because of their smaller size for a given capacitance and lower impedance at high frequencies they are popular in miniature applications such as cellular telephones.

What is RF Transistor?

<p>&nbsp; &nbsp; &nbsp; <strong><a href="http://www.upteks-components.com/01-rf-transistor.html" target="_self">RF transistor</a></strong> is a&nbsp;semiconductor&nbsp;device&nbsp;used to&nbsp;amplify&nbsp;and switch&nbsp;electronic&nbsp;signals. It is made of a solid piece of semiconductor material, with at least three terminals for connection to an external circuit. <a href="http://www.upteks-components" target="_self">RF transistor</a>&nbsp;is a variety of transistors, which is differ from other transistor in its maximum operating frequency. A voltage or current applied to one pair of the transistor's terminals changes the current flowing through another pair of terminals. Because the controlled (output)&nbsp;power&nbsp;can be much more than the controlling (input) power, the transistor provides&nbsp;amplification&nbsp;of a signal. Today, some transistors are packaged individually, but many more are found embedded in&nbsp;integrated circuits.</p>

<p>&nbsp; &nbsp; &nbsp; The transistor is the fundamental building block of modern&nbsp;electronic devices, and is ubiquitous in modern electronic systems. Following its release in the early 1950s the transistor revolutionized the field of electronics, and paved the way for smaller and cheaper&nbsp;radios,&nbsp;calculators, and&nbsp;computers, among other things.</p>

<p>&nbsp; &nbsp; &nbsp; The transistor is the key active component in practically all modern&nbsp;electronics, and is considered by many to be one of the greatest inventions of the 20th century. Its importance in today's society rests on its ability to be&nbsp;mass produced&nbsp;using a highly automated process (semiconductor device fabrication) that achieves astonishingly low per-transistor costs.</p>

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The Application of RF Module

      Radio frequency module (RF module) is the devices usually used to amplify the signal of cable televisions or other electronic equipments, such as wireless cables, stereo sets, etc. An RF module is configurable by a user to operate in different modes as a transmitter, receiver, transceiver, and repeater. RF module can transmit signal from a long distance and it is stable.
      Radio frequency (RF) is a rate of oscillation in the range of about 3 kHz to 300 GHz, which corresponds to the frequency of radio waves, and the alternating currents which carry radio signals. RF usually refers to electrical rather than mechanical oscillations, although mechanical RF systems do exist.

The Steady-state Tantalum Capacitor

The tantalum capacitor is a highly reliable type of solid capacitor or electrolytic capacitor. Surface mount tantalum capacitors are increasingly being used in circuit designs because of their volumetric efficiency, basic reliability and process compatibility. The dynamic reliability of a tantalum capacitor are influenced by several factors under the control of the circuit design engineer. These factors are voltage derating, ripple current and voltage conditions, maximum operating temperature and circuit impedance. Tantalum capacitors possess very low electrical leakage (high leakage resistance), and will retain a charge for a long duration. They are tolerant of hot operating environments up to 125 °C, unlike standard aluminum electrolytic capacitors.

Tantalum capacitors are not particularly tolerant of heavy charge and discharge currents, particularly those of a repetitive nature, and their effective series resistance (ESR) can be high when compared to ceramics or aluminum electrolytics. Most tantalum capacitors are polarized devices; correct polarity must be observed, otherwise the capacitor will depolarize and the dielectric oxide layer will break down, reducing the resistance of the device and causing it to fail. Tantalum capacitors are relatively expensive, particularly the military grades.

The low leakage and high capacity of tantalum capacitors favors their use in sample and hold circuits to achieve long hold duration, and some long duration timing circuits where precise timing is not critical. They are also often used for power supply rail decoupling in parallel with film orceramic capacitors with low ESR and reactance at high frequency. Tantalum capacitors can replace aluminum electrolytic capacitors in situations where the external environment or dense component packing results in a sustained hot internal environment and where high reliability is important. Equipment such as medical electronics and space equipment that require high quality and reliability make use of tantalum capacitors.

 

The Advanced Radar Technology of RF Transistor

       During the war, radar technology is the crucial technique for troops to detect where enemy is. That is to say, in order to give the allies an edge, scientists developed radar technology to "see" for hundreds of miles, even at night. The research that went into improving radar arouses the stage for post-war research into the transistor such as RF transistor.
       In 1940, radar relied on a semiconductor crystal, or "rectifier," to send out a radio wave and analyzing the reflected wave after it bounced off any objects in the air. The rectifier's job was to translate the reflected signal into the direct current necessary for visualization on the screen. Nevertheless, these crystals often couldn't handle the quickness and intensity of a rapidly changing radar signal. They would burn out frequently.
       Finally, after trying different semiconductors and doping with different materials, researchers learned which combinations produced the best results and also learned new techniques on how best to grow and dope the crystals. That was when transistor like RF transistor had been found on that day.

The Powerful Electronic Amplifier—RF Module Amplifier

       Are you often annoyed by the poor quality of your cable television? That’s because you neglect to install the amplifier for your cable. The RF module amplifier is a type of electronic amplifier used to convert a low-power radio-frequency signal into a larger signal of significant power, typically for driving the antenna of a transmitter. It is usually optimized to have high efficiency, high output Power(P1dB) compression, good return loss on the input and output, good gain, and optimum heat dissipation.

       The amplifier is a device for increasing the power of a signal; as a consequence, with the assistance of RF module, the quality of your cable television will improve a lot. Besides using on cable TV, there are other applications of RF module. In audio applications, amplifiers drive the loudspeakers used in PA systems to make the human voice louder or play recorded music.