Kingtronics Blog

Kingtronics manufacturer,  ISO, UL , SGS certified, since 1990.

HC49U 12.000M 20pF +/-30 PPM -10+60'C Bulk RoHS US$0.065/pc
HC49S 10.001M  20pF +/-30 PPM -10+60'C Bulk RoHS US$0.055/pc

Welcome to check our price for crystals, or diode & bridge rectifier.

Please note: diode M7 and LL4148 have stock offer.

You can vist below link to find more information about our Crystals:
http://www.kingtronics.com/quartz-crystals/QKT-HC49SMD.html

A crystal or crystalline solid is a solid material whose constituent atoms, molecules, or ions are arranged in an orderly repeating pattern extending in all three spatial dimensions. The scientific study of crystals and crystal formation is known as crystallography. The process of crystal formation via mechanisms of crystal growth is called crystallization or solidification. The word crystal is derived from the Ancient Greek word κρύσταλλος (krustallos), meaning "rock-crystal" but also "ice", from κρύος (kruos), "icy cold, frost". The word once referred particularly to quartz, or "rock crystal".

Electronic-grade quartz crystal is single-crystal silica which has properties that make it uniquely useful for accurate frequency controls, timers, and filters in electronic circuits. These devices are utilized for a wide variety of electronic applications in communications equipment, computers, aerospace hardware, instruments for commercial use.

Quartz is the second most abundant mineral in the Earth's continental crust, after feldspar. It is made up of a continuous framework of SiO4 silicon–oxygen tetrahedra , with each oxygen being shared between two tetrahedra , giving an overall formula SiO2.

There are many different varieties of quartz, several of which are semi-precious gemstones. Especially in Europe and the Middle East, varieties of quartz have been since antiquity the most commonly used minerals in the making of jewelry and hardstone carvings.

Quartz can use in this luxury goods ,but also use in electrical products. If you can not believe , please visit our website www.kingtronics.com . You will find our Quartz Crystal is very popular in the market right now!

Features

• Low-cost, industry-standard crystal unit
• AT-Cut strip crystal with hermetically sealed can
• Frequency range 3.200MHz to 90.00MHz
• Package height options available

Description

HC-49S crystals share the same base outline as the industry standard HC49 crystal. The crystal uses at AT-cut strip crystal with an hermetically sealed can. HC-49S crystals provide a low cost source of system clock frequency.

Kingtronics manufacture a wide range of quartz crystals. We also stock crystals in most popular package styles, frequencies and specifications for quick delivery.

Kingtronics offers high quality SMD crystals at incredibly aggressive prices. The HC49SMD series is an industry standard crystal package. This is a low cost, low profile timing option for applications where cost is critical．

The HC49SMD is available in tight tolerances and stabilities for demanding applications. With a broad frequency range from 3.200MHz to 90.000 MHz, the HC49SMD can serve as a low cost solution in virtually any application or market. The HC49SD is available in surface mount (SMD) packaging only．

Kt Kingtronics offers leaded quartz crystal HC49U, HC49S and SMD quartz crystal HC49SMD. The quartz crystal market, in general, requires hands on customer service. Quartz crystals are manufactured for frequencies from a few tens of kilohertz to tens of megahertz. More than two billion (2×109) crystals are manufactured annually. We also stock crystals in most popular package styles, frequencies and specifications for quick delivery.

49USMD crystals are low profile surface mount crystals with the same footprint as standard HC49 and HC49-4H crystals. 49USMD crystals are ideal for use in low cost, mass-market applications but are also able to be produced to close tolerances when required. With a broad frequency range from 3.200MHz to 90.000 MHz, the HC49SMD can serve as a low cost solution in virtually any application or market. The HC49SD is available in surface mount (SMD) packaging only.

When choosing a quartz crystal resonator there are many parameters that need to be selected. Many are fairly simple like the tolerance figures. However a few of the others need a little extra explanation. One is the type of resonance. Like any tuned circuit a crystal can have a parallel or series form of resonance as shown. This will have to be specified. If the crystal is to have a parallel resonance then a load capacitance will have to be chosen. This is required because any capacitance across the crystal will alter its resonance slightly. Typically this might be 30 pF, but it will be dependent upon the circuit to be used. Also the tolerance required must be specified. The closer the tolerance, the more expensive the crystal will be, so it is wise not to over-specify the item.

The oscillator circuit of a quartz crystal timepiece is provided with a tuning capacitor device consisting of a stepped variable capacitor and a continuously variable capacitor connected in parallel with each other and in series with said quartz crystal.

In a circuit particularly suited for producing oscillating signals and including a parallel coupled continuous variable capacitor and a step variable capacitor, the improvement comprising said step variable capacitor, and continuously variable capacitor being mounted to a base plate, first and second lower electrodes mounted on said base plate, and means mounted on said base plate electrically connecting said lower electrodes, said step variable capacitor being defined by a fixed dielectric mounted on said first lower electrode, and a plurality of upper electrodes mounted on said fixed dielectric, each of said electrodes having a different area overlapping said lower electrodes, a rotatable electrically conductive first switch contact member selectively positionable in electrical engagement with one of said upper electrodes, and said continuously variable capacitor being defined by an electrically conductive shaft rotatably mounted on said base plate out of electrical engagement with said first and second lower electrodes; a rotatable dielectric mounted for rotation with said shaft partly overlapping said second lower electrodes; a rotatable upper electrode supported by said rotatable dielectric in variable overlapping relation to said second lower electrode and electrically connected to shaft; said switch contact being supported by and electrically connected to said electrically conductive shaft.

Variable Electrical parameters are those that the Design Engineer must specify when selecting a Quartz Crystal device for any particular application.

1. Package Type: Will the package be Through Hole or Surface Mount, and are there size constraints with either.

2. Frequency

3. Load Capacitance: The specified Load Capacitance is dependent on the Resonance Mode required in the application . For Series resonance, no Load Capacitance is required. For Parallel Resonance, the Load Capacitance specified by the Design Engineer will be used to calibrate the Quartz Crystal thereby effecting the major operating characteristics of the device, including initial Frequency Tolerance.

4. Frequency Tolerance: At 25 degree Celsius, an amount of initial frequency deviation acceptable for the application is required. Tighter specifications of Frequency Tolerance lower yield in Quartz Crystal Blank production thereby serving to increase production costs.

5. Stability: Over the Operating Temperature Range, an amount of total deviation acceptable for the application. Tighter specifications of Stability lower yield in Quartz Crystal Blank production thereby serving to increase production costs.

6. Operating Temperature: Standard Operating Temperature ranges are generally considered as -20-+70 degrees Celsius (considered "commercial" Operating Temperature), and -40-+85 degrees Celsius (considered "Industrial" Operating Temperature) Other Operating temperature ranges are available and should be specified.

To analyse the electrical response of a quartz crystal resonator, it is very often useful to depict it as the equivalent electrical components that would be needed to replace it. This equivalent circuit is can then be used to analyse its response and predict its performance. The basic equivalent circuit of a crystal is shown below. In this circuit C1 represents the capacitance between the electrodes. L, C, and R represent the vibrational characteristics of the crystal. The inductance results from the mass of the material, C from the compliance, and R arises from the losses of which the greatest contributor is frictional losses.

Looking at this circuit it can be seen that there are two ways in which the circuit can resonate. One is from the resonance of L and C which provides a series resonance, giving a very low value of impedance at resonance. This is determined by the value of the resistance R. In this mode the external circuit has very little effect on the crystal resonance.