Due to market price fluctuations, if you need to purchase or consult the price. You can contact us or emial to us:   sales@allicdata.com

Transistors - JFETs

The 2N4859UB is a high-performance, low-noise Junction Field-Effect Transistor (JFET) intended for amplifying applications in the commercial and industrial temperature ranges. This particular JFET is designed to produce an ultra-low-noise signal in the electron noise figure at 1.2GHz so as to ensure very accurate signal amplification when used in very sensitive devices.

Applications

The two main applications of the 2N4859UB JFET are general-purpose amplifiers (both audio and radio) as well as video amplifiers. In general, the JFET can be used to control both the gain and frequency response of an audio signal at the output stage of an amplifier. This is because the JFET can produce a very linear response to any input signal while at the same time having a wide dynamic range. Similarly, the JFET can be used in video amplifiers to selectively adjust either the chroma or luminance sections of the signal being amplified.

Working Principle

The JFET operates on the basic principle of controlling the flow of electrons from an input signal to its output. This is done by placing a \'gate\' between the input and output, where the gate acts as a barrier between the two. The voltage of the input signal is then applied across the gate, and depending on the type of JFET transistors used, the gate either opens or closes depending on the applied voltage.

In the case of the 2N4859UB, the gate has a very low input resistance and a fairly high noise figure. This allows the gate to detect and amplify very weak, low-level signals, while at the same time allowing the gate to reject high-level, noisy signals. As a result, the input signal is pulled down to near zero and amplified, producing a very low noise signal at the output.

Conclusion

To conclude, the 2N4859UB JFET is an excellent choice for general-purpose audio and video amplifiers as well as radio amplifiers. Its low-noise, linear response across the wide dynamic range makes it an ideal device for very sensitive applications that require precise amplification.

The specific data is subject to PDF, and the above content is for reference