Transistor is a kind of semiconductor device, which has the functions of amplification, switching, etc. It is one of the indispensable components in modern electronic technology. Before using the triode, it needs to be turned on to make it work normally. Triode has the advantages of small size, low cost, long life, high reliability, and is an indispensable part of modern electronic technology.
Test instruments, such as multimeter CY2305SXC-1HT Oscilloscope, etc. Before switching on the light, you need to understand the basic structure and working principle of the triode.
The basic structure of the triode includes three regions: P-type region, N-type region and P-type region. The N-type area is the thin layer in the middle, called the base area, and the P-type area on both sides, called the emitter and collector. When a small signal voltage is applied to the base area, it will cause the current change in the base area, thus controlling the current change in the collector area. This change can be used as a control signal for amplification or switching.
1、 Features
1. Amplification function: The triode can amplify the input signal by controlling the size and direction of the current when the input signal is very small.
2. Switching function: The triode has the switching function, which can realize the state switching under the action of current and voltage.
3. Voltage stabilizing function: the voltage stabilizing function of the triode can keep the voltage at the output terminal at a fixed value, which is not affected by the fluctuation of the input voltage.
4. Good temperature stability: The triode has good temperature stability and can work normally in a wide temperature range.
2、 Principle
The triode is composed of three different doped semiconductor materials, namely, the emission region, the base region and the collector region. When voltage is applied to the emission area, an electron cloud will be formed, which is the emission source of electrons. The pn junction between the emitter region and the base region is an important part of the control current of the triode.
When a positive voltage is applied to the base of the triode, the electrons in the base area are attracted to the emission area to form a current, which is called collector current. When the voltage of the base is zero, the triode is cut off and the current collection is zero. When a negative voltage is applied to the base, the collecting current will be weakened or completely cut off.
3、 Classification
1. Classification by use: amplification triode, switching triode, voltage stabilizing triode, etc.
2. Classification by structure: NPN type triode, PNP type triode, etc.
3. Classified by operating frequency: low-frequency triode, intermediate frequency triode, high-frequency triode, etc.
4、 Application
1. Amplifier: triode can amplify current, voltage and power, and is widely used in amplifier circuits.
2. Switch: triode can be used to switch circuits, such as flash lamps, electronic clocks, etc.
3. Voltage stabilization: triode can be used for voltage stabilization circuit, such as voltage stabilization power supply, etc.
4. Modulation: triode can be used in modulation circuit, such as amplitude modulation, frequency modulation, etc.
5、 There are many ways to turn on the triode. Here are two common ways:
1. Static lighting method
The static lighting method is a simple method, which only needs to be tested with a multimeter. The specific steps are as follows:
(1) Set the multimeter to the diode test gear.
(2) Connect the emitter and collector of the triode to the two test pens of the multimeter.
(3) Gently press the base of the triode with your finger and observe whether the reading of the multimeter changes.
If the reading changes, the triode has been turned on normally. If there is no change, the base potential needs to be adjusted and retested.
2. Dynamic lighting method
The dynamic switching method requires the use of oscilloscope and other test instruments, which can more accurately detect the working state of the triode. The specific steps are as follows:
(1) Connect the emitter and collector of the triode to two test pens of the oscilloscope.
(2) Connect the trigger electrode of the oscilloscope to the base electrode of the triode, and adjust the trigger potential so that the oscilloscope displays a sinusoidal waveform.
(3) Observe the waveform of the oscilloscope. If amplification occurs, the triode has been turned on normally.
It should be noted that in the process of switching on the triode, special care should be taken to avoid damaging the device. During operation, the following principles shall be followed:
(1) Do not make the emitter and collector of the triode short circuited or inversely connected, or the device will be burned.
(2) Do not let the base of the triode touch any metal object, or it will cause current changes, resulting in error in the test results.
(3) During the test, try to avoid using high voltage or high current to avoid damaging the device.
6、 Precautions for use
1. The static current of the triode shall be within the rated value range, and too large or too small will affect its normal operation.
2. The triode should avoid overheating, otherwise it will be damaged.
3. The temperature change of the triode will affect its working state, so attention should be paid to the temperature change.
4. The triode shall be protected from overvoltage, otherwise it will be damaged.
7、 Development trend
With the continuous development of electronic technology, the function and performance of triode are also constantly improved. The future triode will be more miniaturized, more reliable, lower power consumption, and higher operating frequency to meet the growing demand of electronic equipment for triodes.
