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When buying a crystal oscillator, many customers want the price to be as low as possible. However, at this price, they may end up buying inferior or defective crystal oscillators. How can we quickly identify the quality of a crystal oscillator?
· There are two ways to identify the quality of a crystal oscillator:
There are two ways to identify a crystal oscillator: the first is visual identification (crystal oscillator appearance identification, printed logo identification, crystal oscillator packaging style); the second is multimeter detection;
1. Identify the quality of a crystal oscillator from its appearance, logo, and packaging
(1) Crystal oscillator appearance identification
Appearance inspection is also an important part of the crystal oscillator process. Appearance inspection includes inspections from the shell to the base and leads. If conditions permit, a magnifying glass can be used to inspect from different angles and directions. Check whether the brightness is blurred, whether the shell is clean, etc. There are basically no obvious fingerprints or other debris on the surface of a new crystal oscillator. Secondly, attention should be paid to whether the pressed seal between the shell and the base is neat. A crystal oscillator with rough workmanship can be observed with the naked eye to have gaps on the surface, protrusions and deformations of varying degrees when pressed and sealed, dull, or even slightly yellowed and oxidized. This is a low-quality product. Another type is a second-class product in appearance. Its performance is good, but it fails the appearance test, so it can only be considered a second-class product in appearance.
(2) Identification of printed logos
Features of genuine crystal oscillators: For genuine crystal oscillators produced by the original manufacturer, the front of the shell will enter the next process only after the crystal oscillator test passes. Laser printing is used for printing. The printing is done after the laser machine is debugged. There are strict specifications for the strength and angle of the laser. The overall proportion of the printed size is appropriate, clear and neat, and it looks comfortable. The crystal oscillator manufacturer's logo is highlighted. This is to avoid quality problems of some crystal oscillators, so that customers or manufacturers can trace back and analyze the product causes. What caused it? This is also the difference.
Characteristics of high-quality imitation crystal oscillators:
How to identify high-quality imitation crystal oscillators? Imitation crystal oscillators tend to use neutral words. Because different manufacturers use different laser strengths and angles for laser printing, high-quality imitation products are printed at will. The printing can be used as an important factor in measuring the authenticity of the product. In terms of high-quality imitation workmanship, the shell is usually made of thinner and poorer metal materials. It is easy to penetrate the shell of the crystal oscillator during laser typing, causing the crystal oscillator to leak and produce unstable electrical performance.
(3) Crystal oscillator packaging style
Crystal oscillators shipped from the original factory are all packaged in a unified manner. The packaging style is clean and generous. The outer box has a product label with a clear company trademark or company name. The packaging label contains the main crystal oscillator parameter information such as product model, specification size, accuracy requirements, resistance, quantity, QC inspection confirmation, and production date, which is convenient for customers to check warehousing and production, and is also an important part of product traceability throughout the production process. If the packaging is in appearance, the outer box is torn, the box has been used many times, and has been sealed many times. Each box is different, and each batch of goods has different markings. If you don’t pay attention to the details, you will definitely worry about the quality of such packaging. Therefore, you can see the care in making the crystal oscillator and the seriousness of the customer from the packaging.
2. Method of using a multimeter to detect crystal oscillators
1. Use a multimeter (R×10K range) 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;
2. Use a digital capacitance meter (or the capacitance range of a digital multimeter) to measure its capacitance. Generally, the capacity of a damaged crystal oscillator is significantly reduced (different crystal oscillators have a certain range of normal capacity, which can be measured well, generally tens to hundreds of PF;
3. Shake it close to your ear, if there is a sound, it must be broken (the internal chip has been broken, and if it can still be used, the frequency has changed);
4. Test the output pin voltage. Under normal circumstances, it is about half of the power supply voltage. Because the output is a sine wave (the peak value is close to the source voltage), when measured with a multimeter, it is almost half;
5. Use the substitution method or oscilloscope to measure;
