Bipolar Junction Transistor Connections

Bipolar Junction Transistor is a three terminal device. Whatever may be the use of a transistor either as an amplifier or as a switch it must have one input circuit and one output circuit. To facilitate the input and output circuit a transistor should have four terminals – two for input and two for output … Read more

Parameters of JFET or Specifications of JFET

During purchasing a JFET for a particular application we need to check the specifications of the device. These specifications are provided by manufacturers. The followings are the parameters used to specify a JFET and these are Gate Cut Off Voltage (VGS(off)) Shorted Gate Drain Current (IDSS) Transconductance (gmo) Dynamic Output Resistance (rd) Amplification Factor (μ) … Read more

JFET as A Switch

Both n channel JFET and p channel JFET can be used as a switch. Before going to the actual operation of JFET as a switch we will discuss the basic properties of a switch and then we try to correlate those properties of a switch with the operation of JFET. This will help us to … Read more

Characteristic of Junction Field Effect Transistor

There are two types of junction field effect transistor. N channel JFET P channel JFET Let us discuss the characteristics of n channel and p channel transistor separately one by one for better understanding. Characteristic of N Channel JFET We know that there is a channel of n-type semiconductor material in n channel JFET. The … Read more

Biasing of Junction Field Effect Transistor or Biasing of JFET

Before going to actual topic let us know what is a pinch-off voltage of a junction field effect transistor because it takes a vital role to decide the biasing level of a junction field effect transistor. Pinch Off Voltage In an n channel JFET, if we apply positive potential at drain terminal keeping the source … Read more

Working Principle of Junction Field Effect Transistor or JFET

The bipolar junction transistor is a current controlled device. In this transistor mainly base current controls the operation of the device. In BJT both minority and majority carriers are involved in the operation. On the other hand, a junction field effect transistor is a voltage controlled device, and only majority carriers take part in the … Read more

Q Point or Load Line Analysis of JFET

When we apply an alternating signal to the gate terminal of a JFET, that would be amplified in the drain circuit. The proper amplification of a gate signal depends on proper biasing of both gate and drain section of the JFET. Proper biasing ensures that the JFET is being operated in the active or saturation … Read more

Working Principle of Transistor

There are different types of transistor available in the market, but for sake of understanding, we will consider a common emitter mode of NPN transistor. For this let us recall the basic structural features of npn bipolar junction transistor. Its emitter region is heavily doped and wider hence the number of free electrons (majority carriers) … Read more

Pulse Rate Measurement

When heart muscles contract, ventricles eject blood and a pressure is transmitted along the circulatory system. When the pressure travels through vessels, it causes vessel displacement. The displacement is measurable at various points in circulatory system. This pulse is felt when fingertip is placed over the radial artery on the wrist or other location where … Read more

Apnoea Detectors

What is Apnoea? The stoppage of breathing is apnoea, which leads to arrest of heart circulation. Apnoea occurs due to head injury, drug overdose, etc. It occurs in premature babies during first weeks of life due to undeveloped nervous system. Apnoea has to be treated else, it will lead to problem in brain function. Therefore, … Read more