Characteristics of Junction field effect transistor (JFET)
- Temperature sensitivity: The JFETs are sensitive to temperature variations, which allows them to adapt their properties with changing temperatures. In certain applications, proper thermal management may be necessary.
- Low Noise: JFETs are known for their low noise, which is valuable in applications such as amplifier and sensors where signal integrity is essential.
- High input impedance: The high input impedance of JFETs remains relatively stable over a range of temperatures and voltages, making them suitable for precision applications.
- Variants: JFETs, which allow circuit design flexibility and enable applications that require both sourcing and sinking current, are available in two types of channels: N channel and P Channel.
Other characteristics majorly followed are mentioned below:
- Output characteristics
- Transfer characteristics
Output Characteristics of JFET
The output characteristics of the JFET were plots between drain current (Id) and drain source voltage (Vds). These characteristics find the variation of drain current concerning the voltage applied at the drain-source terminals while keeping the gate-source voltage constant.
Basically, the characteristics are of two types: output characteristics, or drain characteristics, and transfer characteristics.
Terminologies involved in output characteristics of JFET:
- Saturation region: In this region, the JFET operates with low Vds, and the current is constant. The current is controlled by the gate source voltage (Vgs).
- Ohmic region: JFET becomes an ohmic region with increasing VDS. The drain current increases with Vds.
- Pinched off region: By increasing the VDS, it can lead to a pinch of region; in this region, the channel narrows and the drain current becomes independent of the VDS.
- Breakdown Region: As the voltage of drain source becomes very high then the JFET channels gets breakdown and current flows in an uncontrolled manner.
Transfer Characteristics of JFET
The transfer characteristics of a JFET plotted between the drain current (Id) and drain source voltage (Vds). It can be determined by keeping the Vds constant and drain current can be observed by changing the gate source voltage. So we can observe that when the gate source voltage Vgs is increased, the drain current Id decreases. When the drain source voltage is constant, it can be observed that the value of the drain current varies inversely with respect to the gate source voltage. The above transfer characteristics curve of JFET is described below; it can be observed that the value of drain current varies inversely with respect to gate-source voltage (vgs) when the drain-source voltage is constant.
Junction Field Effect Transistor or JFET
In electronics, the junction field effect transistor is a fundamental component, operating on the principle of electric field control. It is a three-terminal device, and it consists of the gate, drain, and source terminals.
There are two types of JFETs: N-channel JFET and P-channel JFET. The N channel JFET controls the flow of current through electrons, while the P channel JFET depends on the movement of the holes where the electrons are absent. The gate terminal plays a major role in conducting current and controls the electron flow from source to drain. JFETs are also useful in switching circuits because they can be used as voltage-controlled resistors.
In this article, we will learn about what is JFET and key terminologies, construction and working of JFET and types of JFET, features, and characteristics, applications of junction field effect transistors in detail.
Table of Content
- What is JFET?
- Key terminologies
- Construction
- Working
- Types of JFET
- Characteristics
- Applications