When the winter arrived, a cold current came, and some of the human body was poor. The cold and cold changes in the environment could not be affected. This shows that illness is related to your own physique.
In the circuit, there are also physical strengths：
Resistance, inductance, capacitors, semiconductor devices (including diode, triode, field tube, integrated circuit), that is, under the same working conditions, the probability of damage to semiconductor devices is the largest.
Therefore, when we look for faulty elements, we must give priority to checking diodes, triode, field pipes, integrated circuits, etc. When general semiconductor devices are damaged, it is more common when it is damaged. The resistance of the knot is about 500. If 80 % of the bee is broken, it can be removed and tested to confirm.
We all know that the first sister -in -law is bad, and the head guards must be prepared at any time, which shows that the job determines the degree of danger.
In the circuit, components working in high voltage, large current, and high power are undoubtedly affordable, and the possibility of damage is high. It is also the key element and functional elements of the circuit.
Any place in a large current is large (the law of Jiaoer ascension -the square of the calories is proportional to the square of the current), so all components with heat sink are easy to be damaged. High -power resistance is also easy to be damaged. How can a high -power resistor be seen? It has nothing to do with its resistance value. It is only related to its volume. The larger the volume, the greater the power. In the circuit, the fuse and insurance resistance are the least insurance elements. First of all, because its melting point is low, it is easy to break. Because it is the insurance of other people, it rushes to the front line. When it is a police officer, it is bad when it is bad.
The component is damaged, with over pressure damage, overcurrent damage, and of course mechanical damage. Damage damage such as lightning strikes, break through the bridge rectifier. Overcurrent damage, such as the heating of the monitor row tube.
There are various ways to die corresponding to others. If the pressure is beheaded, the person's head is falling, the person is dead, and the body is intact. There is no obvious changes outside the component damage component, but the parameters have changed. Overwhelming like poisoning and death, it can still be banned from the beginning, and it is getting more and less. When it is dead, it is already bruised and blurred in the body. The surface temperature of overcurrent damaged components is very high, and it has obvious changes in cracks, discoloration, and small pit. In severe cases, the circuit board around the component becomes yellow and black.
Commonly used electronic components can use digital universal meters to do some simple tests when the appearance looks abnormal.
resistance
Test resistance is right.
diode
Test the pressure drop of the PN knot with a digital multimeter can be compared with the intact diode of the same model.
triode
Whether it is the n tube or the P tube, the two PN knots can be measured with a digital multimeter.
Field effect tube
Whether the PN knot of the diode in the body of the test field effect tube is normal, test GD, and whether there are short circuits in GS.
capacitance
Unexpected capacitors, breakdown in short -circuit or off -welding, severe leakage or resistance effect.
The effectiveness of the electrolytic capacitance is: breakdown, increased power leakage, smaller capacity or disconnection.
inductance
The practical characteristics are: disconnect, off -welding
chip
The internal structure of the integrated circuit is complex and has many functions, and any part of the damage cannot work properly. There are also two types of integrated circuits: completely damage and poor thermal stability. When it is completely damaged, it can be removed, and the positive and reverse resistance of each pin to the ground compared with the normal integrated circuit of the same model, and one or more of the pin resistance value can always be found.
For those who have poor thermal stability, you can use the integrated circuit that is cold but suspected when working in equipment. If the failure time is delayed or no failure occurs, you can determine it. New integrated circuits can usually be replaced to eliminate.
Whether it is a fault in natural loss or the failure of human damage, it can generally be attributed to three types of failure of circuit connection, electronic component damage and software failure. If the connection is open, if it is the broken of the wire, the breaks of the plug -in, poor contact, etc., it is generally easier to repair.
And the damage of electronic components, (except for obvious burning, heating), is generally difficult to find that in many cases, in many cases, you must use the instrument to detect and judge. Therefore, for technicians, you must first understand various devices. The characteristics of effectiveness, which is extremely important for the failure of the maintenance circuit and improving the efficiency of maintenance.
For more electronic components requirements,pls see:https://www.megasourceel.com/products.html