How to distinguish the crystal oscillator of chip components in SMT chip processing A-987

With the advancement of electronic technology, the plug-in crystal oscillators used on a large scale in the past have been replaced by small, thin and light chip crystal oscillators. The plug-in crystal oscillators that everyone knows before are generally 2-pin, but the SMD crystal oscillators are different. Let’s clarify the specifications of the chip crystal oscillator.
First, the 2-pin SMD crystal oscillator must be a passive crystal oscillator. The 4-pin SMD crystal oscillator may be a passive crystal oscillator or an active crystal oscillator. The SMD crystal oscillator with more than four pins must be an active crystal oscillator. The active crystal oscillator itself is printed There is a dot on the lower left foot.
SMD component crystal oscillator
Common SMD crystal oscillator specifications are: 2.5*2.0mm; 3.2*2.5mm; 5.0*3.2mm; 6.0*3.5mm; 5.0*7.0mm.
2-pin passive SMD crystals are usually more common with ceramic surfaces, of course, there are also metal surfaces, but generally speaking, four-pin passive SMD crystals are the main ones for metal surfaces.
When we use SMD crystal oscillators, we usually encounter the following situations. The four-pin SMD crystal oscillator does not know how to distinguish the pins. In the case of a passive crystal oscillator with four pins, only two pins are functional pins, and the other two pins are suspended and do not need to be connected. We call it 1 foot, 2 foot, 3 foot, 4 foot. Under normal circumstances, how to distinguish who is 1 foot and who is 2 feet. Here is a trick to tell everyone.
Four-pin passive SMD crystal oscillators, crystal oscillator manufacturers let everyone distinguish the pin positions in order to be more advantageous. There is usually a gap on the first leg, which counts down clockwise as 1, 2, 3, and 4. Passive crystal oscillator feet 1 and 3 are grounded, and feet 2 and 4 have no function.
In addition, active crystals are usually distinguished by dots. The position of the silk screen point is foot 1. Turn it over and count it clockwise, and the direction of the foot will be clear. Active crystal oscillators can be divided into the following categories; quartz oscillators, temperature-compensated oscillators, voltage-controlled oscillators, and voltage-controlled temperature-compensated oscillators.