FET, what is the difference between depletion and enhancement

First, the reference is different.

1. Depletion type: that is, a device that can conduct electricity at 0 gate bias.

2. Enhanced: that is, it is a device that is not conductive at 0 gate bias, that is, only when the magnitude of the gate voltage is greater than its threshold voltage.

conductive channel FETs.

Second, the characteristics are different.

1. Depletion type: MOSFET.

The source and drain are structurally symmetrical and can be used interchangeably, depleting MOS tubes.

The gate - source voltage can be positive or negative. Therefore, the use of MOSFETs is more flexible than transistors.

2. Enhanced: The original channel of the enhanced type is narrower and the doping concentration is low, so that the channel is pinched off when the gate voltage is 0, and the channel is generated and conductive only when the positive gate bias voltage is added (it must be less than . The output volt-ampere characteristics are still saturated.

Third, the principle is different.

1. Depletion type: when VGS=0, the channel is formed, and when the correct VGS is added, most carriers can be made.

The flow out of the channel "depletes" the carriers, causing the tube to turn to cut-off.

2. Enhanced: When VGS=0, the tube is in a cut-off state, and after adding the correct VGS, most of the carriers are attracted to the gate, thus "enhancing" the carriers in the region and forming a conductive channel.

The differences between an enhanced MOSFET and a depleted MOSFET are as follows:

1.Works differently. When the gate voltage is zero, there is a large drain current, which is called the depletion type, that is, the depletion type MOSFET. When the gate voltage is zero, the drain current is also zero, and a certain amount of gate voltage must be added before the drain current is called enhanced, that is, the enhanced FET.

2.The drain and source depletion layers of the depletion type MOSFET cannot be turned on without adding the gate source voltage, and the gate source voltage can only be positive.

3.The enhanced MOSFET can be turned on, and the gate-source voltage can be positive or negative.

Both the depletion type and the enhanced type belong to the MOS transistor (insulated gate type FET). In the former, the drain and source depletion layers cannot be turned on without adding the gate-source voltage, and the gate-source voltage can only be forward. The enhanced type can be turned on, and the gate-source voltage can be positive or negative.

When the gate source voltage VGS is 0, the drain current is also 0 The tube is an enhanced tube.

When the gate-source voltage VGS is 0, the drain current is not 0 and the tube is a depletion tube.

It's all half like this and half like that.

First, the reference is different.

1. Depletion type: that is, a device that can conduct electricity in the banquet hole when the gate bias voltage is 0.

2. Enhanced: that is, a device that is not conductive at 0 gate bias, that is, a field-effect transistor with a conductive channel can only appear when the magnitude of the gate voltage is greater than its threshold voltage.

Second, the characteristics are different.

1. Depletion type: The source and drain of the FET are symmetrical in structure and can be used interchangeably, and the gate-source voltage of the depletion MOS transistor can be positive or negative. Therefore, the use of MOSFETs is more flexible than transistors.

2. Enhanced: The original channel of the enhanced type is narrower and the doping concentration is lower, so that the channel is pinched off when the gate voltage is 0, and the channel is only generated and conductive when the gate bias voltage is added (it must be less than . The output volt-ampere characteristics are still saturated.

Third, the principle is different.

1. Depletion type: when VGS=0, the channel is formed, and when the correct VGS is added, most of the carriers can flow out of the channel, thus "exhausting" the carriers and making the tube turn to cut-off.

2. Enhanced: When VGS=0, the tube is in a cut-off state, and after adding the correct VGS, most of the carriers are attracted to the gate, thereby "enhancing" the carriers in the area and forming a conductive channel.

Two-phase PT (Potential Transformer) and three-phase PT have the following differences:

1.Wiring method: The two-phase PT has two terminal blocks for measuring the voltage of the two-phase system. The three-phase PT has three terminal blocks for measuring the voltage of the three-phase system.

2.Measurement object: Two-phase PT is suitable for the measurement of two-phase power system or two-phase load, single-phase transformer or single-phase load.

Whereas, three-phase PT is suitable for the measurement of three-phase power systems, such as three-phase transformers or three-phase loadsElectrical parameters: The two phases usually have two groups around the leakage stove, which are connected separately.

Whereas, a three-phase PT usually has three windings connected to three wires.

4. Scope of use: Two-phase PT is usually used in small power systems or specific application scenarios, such as residential special industrial equipment. The three-phase PT is widely used in the industrial electrical, phase system, and the three-phase system. The selection of the appropriate PT type should be determined according to the actual power demand.

Now more and more electronic circuits are using FET, especially in the field of audio, FET is different from transistor, it is a voltage control device (transistor is a current control device), its characteristics are more like electron tubes, it has a high input impedance, large power gain, because it is a voltage control device so the noise is small, its structure is simplified as shown in Figure C-a

The MOSFET is a unipolar transistor, it has only one p-n junction, in the state of zero bias, it is on, if a reverse bias voltage (called gate bias) is added between its gate (g) and source (s) under the action of the reverse electric field, the p-n thickens (called the depletion region) and the channel narrows, its drain current will become smaller, (as shown in Figure C1-b), when the reverse bias reaches a certain level, the depletion region will be completely channeled"Clipping"At this time, the MOSFET enters the cut-off state as shown in Figure C-C, and the reverse bias at this time is called the pinch voltage, which is represented by VPO, which can be expressed as VPo=VPS+|vgs|, here|vgs|is the absolute value of VGS.

In the manufacture of MOSFET, if before the gate material is added, a thin layer of insulation is added to the channel, the gate current will be greatly reduced, and its input impedance will be greatly increased, due to the existence of this insulation layer, the MOSFET can work in a positive bias state, we call this MOSFET insulated gate FET, also known as MOS FET, so there are two types of MOSFET, one is an insulated gate FET, it can work in the reverse bias, zero bias and forward bias state, one is a junction gate effector, which can only work in the reverse bias state.

Insulated gate FET is divided into two types: enhanced and depleted, we call the depletion FET that is turned on under normal conditions, and the enhanced FET that is disconnected under normal conditions. Characteristics of the enhanced MOSFET: when VGS=0, ID (drain current) = 0, only when VGS increases to a certain value, it starts to turn on, and there is a drain current.

It is also said that the gate-to-source voltage VGS when the drain current begins to occur is the turn-on voltage.

The depletion MOSFET is characterized by the fact that it can operate at positive or negative gate-source voltages (positive or negative bias) and that there is essentially no gate current (very high input resistance) at the gate

Insulated gate FET can be used for circuits used in junction gate FET applications, but circuits used in insulated gate reinforced FET applications cannot be replaced by junction gate FET applications.

In MOSFETs, with the increase of UGS, a depletion layer is formed on the surface of the P-type substrate close to the silica insulator.

Field Effect Transistor (FET)) is abbreviated as Field Effect Transistor. There are two main types (junction FET-JFET) and metal-oxide semiconductor FET (MOS-FET). Conducted by a majority of carriers, it is also known as a unipolar transistor.

It is a voltage-controlled semiconductor device. It has the advantages of high input resistance (107 1015), low noise, low power consumption, large dynamic range, easy integration, no secondary breakdown phenomenon, wide safe working area, etc., and has become a strong competitor of bipolar transistors and power transistors.

A field effect transistor (FET) is a semiconductor device that uses the electric field effect of the control input loop to control the output loop current, and is named after it.

Because it conducts electricity only by the majority of the carriers in semiconductors, it is also known as a unipolar transistor.

No, the differences between an enhanced MOSFET and a depleted MOSFET are as follows:

1.Works differently. When the gate pressure is zero, there is a large drain current, which is called the depletion type, that is, the depletion type FET.

When the gate voltage is zero, the drain current is also zero per mu, and a certain gate voltage must be added before the drain current is called enhanced, that is, the enhanced FET.

2.The drain and source depletion layer of the depletion type FET cannot be turned on when the gate source voltage is not large, and the gate source voltage can only be forward.

3.The enhanced MOSFET can be turned on, and the gate-source voltage can be positive or negative.

Generally speaking, the Zeng strong MOSFET cannot replace the depletion MOSFET. The depletion type MOSFET is characterized by its high impedance, which can reduce the voltage of the input signal, while the Zeng strong type MOSFET does not have such a function. In addition, the depletion type MOSFET can also be used to provide a function of amplifying the output current in some circuits, while the pin content characteristics of the Zeng strong type MOSFET are stable and cannot be used to amplify the high current.