Is BJT a voltage controlled or current controlled device?

as in the base region movement of charge carrier is because of the electrons which is minority charge carrier in the base region. So a BJT can said to be minority current controlled device. Base current flows between base and emitter in the BJT to induce a larger current flow between emitter and collector.

Also to know is, is FET a current controlled device?

Why JFET is called voltage controlled device while BJT is called current controlled device? My question is why JFET/FET is called voltage controlled device while BJT is called current controlled as both required voltage to operate properly.In both electric field is produced so why is the difference?

What is a current mode controller?

Voltage mode and current mode are the two regulating conditions that control the output of the supply. Most applications call for a supply to be used as a voltage source. In these applications, the power supply runs in voltage mode, maintaining a constant output voltage while providing the required current to the load.

What is current controlled devices?

BJT is a current controlled device, where the base current (Ib) is used to drive the BJT either ON or OFF, whereas, a MOSFET is a voltage controlled device, the gate voltage is used to control the switching activities.

What is the difference between BJT and FET?

BJTs, FETs and MOSFETs are all active semiconductor devices, also known as transistors. BJT is the acronym for Bipolar Junction Transistor, FET stands for Field Effect Transistor and MOSFET is Metal Oxide Semiconductor Field Effect Transistor.

What is a current controlled voltage source?

In the theory of electrical networks, a dependent source is a voltage source or a current source whose value depends on a voltage or current somewhere else in the network. Dependent sources are useful, for example, in modelling the behavior of amplifiers.

Why FET is used as voltage controlled device?

The MOSFET, like the FET, is a voltage controlled device. A voltage input to the gate controls the flow of current from source to drain. The gate does not draw a continuous current. Though, the gate draws a surge of current to charge the gate capacitance.

Why is a transistor called a current controlled device?

BJT transistor are current controlled devices but FET transistor are voltage controlled devices. BJT transistors are called current-controlled devices because the collector current is controlled by the base current, according to the ratio called Beta.

Why is it called a transistor?

The name transistor is a combination of the words transfer and resistor – a transfer resistor – a transistor. When it was announced the name was explained; “because it is a resistor or semiconductor device which can amplify electrical signals as they are transferred through it from input to output terminals.”

Why the transistor is called a current controlled device?

A MOSFET is known as a voltage controlled device because a voltage applied to the gate controls the flow of current between the source and drain. For a BJT the principal is the same. It is a current controlled device because the base current controls the current flow from the emitter to collector.

What is meant by current controlled device?

You can understand this by the following examples, a BJT is a current controlled device because its output characteristics are determined by the input current while a FET is voltage controlled device because its output characteristics are determined by the Field which depends on Voltage applied.

Is FET a current controlled device?

Why JFET is called voltage controlled device while BJT is called current controlled device? My question is why JFET/FET is called voltage controlled device while BJT is called current controlled as both required voltage to operate properly.In both electric field is produced so why is the difference?

Why it is called field effect transistor?

The field-effect transistor (FET) is a transistor that uses an electric field to control the electrical behaviour of the device. FETs are also known as unipolar transistors since they involve single-carrier-type operation.

Why do we use BJT?

BJT (bipolar junction transistor) are widely used an amplifier, oscillator, switch etc. It is a current-driven device (MOSFET is voltage driven), the output current is equal to the input current times a factor which is called Gain. A basic BJT has three pins: the Base, Collector, and Emitter.

Why BJT is called bipolar junction transistor?

Bipolar transistors are so named because the controlled current must go through two types of semiconductor material: P and N. The current consists of both electron and hole flow, in different parts of the transistor. Bipolar transistors consist of either a P-N-P or an N-P-N semiconductor “sandwich” structure.

Is Mosfet a current controlled device?

MOSFET Field effect transistor is a unipolar- transistor, which acts as a voltage-controlled current device and is a device in which current at two electrodes drain and source is controlled by the action of an electric field at another electrode gate having in-between semiconductor and metal very a thin metal oxide

How does the base current control collector current?

The base current increase (decrease) is due to an increase (decrease) in vBE. The increase (decrease) in vBE increases (decreases) the injection of carriers from the heavily doped emitter. Then, for these numbers, the collector current changes by 4% when the base-emitter voltage changes by 1mV.

Why is FET known as a unipolar device?

All FETs can be called UNIPOLAR devices because the charge carriers that carry the current through the device are all of the same type i.e. either holes or electrons, but not both. This distinguishes FETs from the bipolar devices in which both holes and electrons are responsible for current flow in any one device.

What do you mean by pinch off voltage?

Pinch off voltage: Pinch off voltage is the drain to source voltage after which the drain to source current becomes almost constant and JFET enters into saturation region and is defined only when gate to source voltage is zero.

Why BJT is called a bipolar device?

A bipolar junction transistor (bipolar transistor or BJT) is a type of transistor that uses both electron and hole charge carriers. In contrast, unipolar transistors, such as field-effect transistors, only use one kind of charge carrier. The basic function of a BJT is to amplify current.

What is Beta’s current ratio?

A transistors current gain is given the Greek symbol of Beta, ( β ). As the emitter current for a common emitter configuration is defined as Ie = Ic + Ib, the ratio of Ic/Ie is called Alpha, given the Greek symbol of α. Typically, Beta has a value between 20 and 200 for most general purpose transistors.

Why the input impedance of FET is so high?

Contrast this with the BJT. Hence, a BJT is current controlled , where as a n FET is voltage controlled. Naturally, you know that a reverse biased diode junction is like a open circuit, showing ideally infinite impedance. So, the reverse biased gate input of the FET is the cause of its high input impedance.

What is the difference between Transistor and Mosfet?

Difference Between BJT and MOSFET. The transistors BJT and MOSFET are both useful for amplification and switching applications. Basically, the mode of operation of a BJT transistor is driven by the current at the base. The three terminals of a BJT transistor are called the Emitter, Collector and Base.

What is current controlled devices?

BJT is a current controlled device, where the base current (Ib) is used to drive the BJT either ON or OFF, whereas, a MOSFET is a voltage controlled device, the gate voltage is used to control the switching activities.