Does a passive crystal oscillator have a direction?
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Does a passive crystal oscillator have a direction?
Passive crystal oscillators have no direction, and their pins have no positive or negative polarity.
How to identify the direction of a passive crystal oscillator? Will there be any problems if a passive crystal oscillator is pasted upside down?
First of all, it is necessary to make it clear that crystal oscillators are divided into two categories: passive crystal oscillators and active crystal oscillators. Passive crystal oscillators are called Crystal in English, and the full name in Chinese is quartz crystal resonator. Some people also like to call passive crystal oscillators crystals. Active crystal oscillators are called Oscillator in English, and the full name in Chinese is quartz crystal oscillator, also known as clock oscillator, and some people simply call it OSC.
Two-pin passive crystal oscillator: one pin is the frequency output pin, and the other pin is the frequency input pin. Even if it is reversed, the crystal oscillator still works normally.
Four-pin patch passive crystal oscillator: Generally, pins 1 and 3 are the frequency input pin and frequency output pin, and the other two pins (pin 2 and pin 4) are ground pins. Even if it is rotated 180 degrees, only pins 1 and 3 are swapped, that is, the input pin becomes the output pin, and the output pin becomes the input pin. The crystal oscillator can still work normally and will not cause any performance and function differences.
| Footer Notes |
| 1 foot |
In/Out |
| 2-pin |
GND |
| 3-pin |
In/Out |
| 4-pin |
GND |
Active crystal oscillators have directionality, and if they are attached upside down, they will be damaged by the current. Passive crystal oscillators, on the other hand, have no directionality, so it doesn't matter if they are attached upside down. In other words: no matter whether the passive crystal oscillator is plug-in type or SMD type, or has two or four pins, when attaching or welding, there is no distinction between positive and negative poles, and there is no directionality, so don't worry about attaching it upside down.
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