Why can semiconductor transistors be used as amplifier devices, and what is the principle of amplifi

Triode current amplification. In the case of setting the static operating point, for the common emission stage circuit, the signal is input from the base, and the resistor is connected at the C or E pole, and the change of current is converted into a change in voltage output.

Knowing the amplification principle of the transistor, you can make an audio amplifier.

Look for a book that simulates electronics.

Summary. A negative number of current indicates that the direction of the current is opposite to the direction of the voltage.

For example, let's say that ... UAB has a voltage of 10 between A B and a resistance of 10K at both ends of the resistor R. Then the current IAB = 1MA The current direction is from A to B The current is IBA=-1 The current direction is from B to A...

For more information, please refer to Chapter 1 of Circuit Basics.

As you can deduce, the transmitting stage of the transistor is grounded in the AC path, i.e., UCE is the voltage from point C to ground. The voltage at point C should be the current flowing through RC RL multiplied by the resistance (Ohm's law, i.e. you have no negative part), and the direction of the current flow through the parallel resistance at point C to ground. However, the direction of the IC is the same size and the opposite direction.

So when calculating, add a negative.

Hello, I have seen your question and am sorting out the answer, please wait a while The negative number of the current indicates that the direction of the current is opposite to the direction of the voltage. For example, let's say that ... UAB has a voltage of 10 between A B and a resistance of 10K at both ends of the resistor R.

Then the current IAB = 1MA The current direction is from A to B The current is IBA=-1 The current direction is from B to A... For more information, please refer to Chapter 1 of Circuit Basics. As you can deduce, the transmitting stage of the transistor is grounded in the AC path, i.e., UCE is the voltage from point C to ground.

The voltage at point C should be the current flowing through RC RL multiplied by the resistance (Ohm's law, i.e. you have no negative part), and the direction of the current flow through the parallel resistance at point C to ground. However, the direction of the IC is the same size and the opposite direction. So when calculating, add a negative.

A transistor is composed of two N-type or P-type diodes sandwiched between a layer of P-type or N-type diodes, and is divided into a collector, a base, and an emitter. The collector is responsible for replenishing energy, the base is responsible for trigger control, and the firing sock is responsible for output. Due to its special structure, the amount of electrons injected in the emission region is several times the amount of electrons at the base, when the base signal current is turned on, the emitter current emission is triggered, such as the base enters an electron, the emitter may flow out of several or hundreds of electrons, so as to achieve the so-called current amplification.

1) In order to facilitate the emission of electrons by the emission junction, the doping solubility of the semiconductor in the emission region is much higher than that of the semiconductor in the base region, and the area of the emission junction is small.

2) Although the emission area and the collector area are doped semiconductors of the same property, the doping solubility of the emission area is higher than that of the collector area, and the area of the collector junction is larger than that of the transmitting junction, which is convenient for collecting electrons.

3) The base region of the two PN junctions connecting the emission junction and the collector junction is very thin, and the doping solubility is also very low.

The amplification circuit is the use of electronic components with amplification characteristics, such as crystal transistors, after the transistor plus the working voltage, the small current change at the input end can cause the change of the larger current at the output end, and the change at the output end is several times to hundreds of times greater than the change at the input end, which is the basic principle of the amplification circuit.

To calculate the current and interpole voltage of the transistor, a direct current path (capacitor open circuit) should be used.

Base current: IB=IBQ=(VCC-VBEQ) RB collector current: IC=ICQ= IBQ

The basic principle of the transistor amplification circuit is to use the amplification characteristics of the transistor to increase the amplitude of the input signal. A transistor is a semiconductor device that consists of a base, emitter, and collector. In amplification circuits, bipolar transistors are typically used, which can be used to amplify voltage, current, or power.

The basic principle is as follows:

Input signal: The input signal is added to the base of the transistor through the input terminal. As the input signal increases, the voltage between the base and emitter also changes.

Activate the transistor: When the input signal is applied to the base, the voltage between the base and emitter is changed, causing the transistor to operate in a different state. This change causes a change in the current between the emitter and collector.

Output signal: The current change between the emitter and collector causes the output signal to increase, which enables the input signal to be amplified.

Through the reasonable design of the circuit, the amplification characteristics of the transistor can be fully utilized, so as to achieve effective amplification of the input signal. This is the basic working principle of a transistor amplification circuit.

Triode Amplification Circuit Fundamentals: An explanatory document on the principles of transistor circuits.

Because the collector current of the triode and the base current in the amplification area are basically constant proportional relationship, so a small base current can be used to control the larger collector current, which is the current amplification function of the triode, the signal voltage is converted into the base current of the triode through the resistance, and then the collector current of the triode is converted into voltage through the resistance, which realizes the voltage amplification.

Can the transistor still work if it doesn't supply more current? Today is a long time to see.

I see that they say so much, and you may not understand why it is magnifying, so let me give you an example that is easier to understand

We can think of the transistor as a lever, as long as the arm is long enough and the torque is large enough. You can carry very heavy things with very little effort. The fulcrum position of the lever can be understood as the magnification value of the triode b, and the b value depends on the static bias of the transistor and the physical characteristics of the transistor itself.

The power amplification of the lever depends on the pivot position and the hardness of the lever itself. The magnifying tube has a saturation zone, and the lever also has a time to bend.

The relationship between the two of them is really similar, there are linear and non-linear regions.