How to judge the quality of ceramic crystal oscillator
Use the capacitance block of the DT890 digital multimeter to detect the capacity of the crystal oscillator, which can quickly and accurately judge the quality of the crystal oscillator.
First adjust the DT890 digital multimeter to the capacitance of 2000pF, and then use the two test leads to touch the two pins of the crystal oscillator, and the multimeter will display the capacity of the crystal oscillator under test. When the measured capacity of the crystal oscillator is between 200″-300pF (individually up to 500pF), it can be judged to be good; when the capacity is much less than 200pF, the ceramic chip is broken, mostly caused by collision; when the capacity is much larger than 500pF When the crystal is leaking, it is mostly caused by moisture; when the measured crystal has no capacity, it is an open circuit between the poles, which is mostly caused by quality problems. In addition, when measuring the static capacitance of the crystal, if the value displayed on the multimeter is unstable and The change is greater than 20pF, indicating that the crystal is deteriorated and damaged.
The above method is suitable for testing crystal oscillators with resonant frequencies of 432kHz, 455kHz, 480kHz, 500kHz, and 503kHz to judge whether they are good or bad.
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