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How to judge the quality of electronic components

PCB board factory: As we all know, electronic equipment is composed of small electronic components, with various types of components and complex functions, just like a small card in a domino. Once one of the cards falls, the others Will also be heard. Therefore, ensuring that each component has good functionality is one of the necessary skills for electronic maintenance personnel. So how to judge the quality of electronic components? To share some common electronic component testing experience and skills today!

Electronic component inspection

Judge the quality of the crystal oscillator

First use a multimeter (R*10k block) to measure the resistance value at both ends of the crystal oscillator. If it is infinite, it means that the crystal oscillator has no short circuit or leakage; then insert the test pencil into the mains socket, and pinch any pin of the crystal oscillator with your finger The other pin touches the metal part on the top of the test pencil. If the neon bulb of the test pencil turns red, it means that the crystal oscillator is good; if the neon bulb is not bright, it means the crystal oscillator is damaged.

Polarity recognition of bidirectional thyristor
The bidirectional thyristor has unique properties. Based on these properties, we can easily identify the control electrode of the bidirectional thyristor by measuring the resistance between the electrodes. When the black test lead is connected to the main electrode 1 and the red test lead is connected to the control electrode, the measured forward resistance is always smaller than the reverse resistance. Therefore, we can easily identify the main electrode 1 and the main electrode by measuring the resistance. .

Check the quality of the light-emitting digital tube
First set the multimeter to the R*10k or R*100k block, then connect the red test pen to the “ground” terminal of the digital tube (take the common cathode digital tube as an example), and the black test pen sequentially connects to the other terminals of the digital tube. They should emit light separately, otherwise the digital tube is damaged.

Measure the leakage resistance of large-capacity capacitors
Use a 500-type multimeter to set the R*10 or R*100 block, and when the pointer points to the maximum value, immediately switch to the R*1k block to measure. The pointer will stabilize in a short period of time, thereby reading the leakage resistance value.

Determine the polarity of unsigned electrolytic capacitors
First short-circuit the capacitor and discharge it, then mark the two leads A and B, set the multimeter to R*100 or R*1k, connect the black test lead to the A lead, and the red test lead to the B lead. Read the reading after the pointer is still stationary. After the short-circuit discharge; then connect the black test lead to the B lead, and the red test lead to the A lead. Compare the two readings. The black test lead with the larger resistance value is connected to the positive electrode, and the red test lead is connected to the negative electrode.

The above are some tips on how to judge the quality of electronic components. This article will first describe five small methods for judging the quality of components for the time being! There are more ways to judge the quality of components, please pay close attention to the next article!

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