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.

In electronics, a varicap diode, varactor diode, variable capacitance diode, variable reactance diode or tuning diode is a type of diode which has a variable capacitance that is a function of the voltage impressed on its terminals.

All diodes exhibit this phenomenon to some degree, but specially made varactor diodes exploit the effect to boost the capacitance and variability range achieved - most diode fabrication attempts to achieve the opposite.

In the figure we can see an example of a crossection of a varactor with the depletion layer formed of a p-n-junction. But the depletion layer can also be made of a MOS-diode or a Schottky diode. This is very important in CMOS and MMIC technology.

For a 10uF capacitor we recommend using a 1206 footprint, and for 22uF and 47uF we recommend a 1210 footprint. The 1812 footprint is slightly better than the 1210 for the 47uF, but we don’t think the improvement is worth the extra space and added cost.

Sometimes the product cost may also impact the chosen footprint. For example, if a 1210, 22uF capacitor is more than double the cost of a 1206, then the 1206 component may be preferred. In other applications, the designer may just want to get the maximum capacitance in a limited available footprint. If, for example, there is only room for a 1206 capacitor, the 47uF part will still have the most capacitance even if it loses a larger percentage of its value than the 22uF or the 10uF parts.

MLCC consists of a conducting material and electrodes. To manufacture a chip-type SMT and achieve miniaturization, high density and high efficiency, ceramic condensers are used. WTC’s MLCC is made by NPO, X7R and Y5V dielectric material and which provides product with high electrical precision, stability and reliability.

For chip multilayer ceramic capacitors, Kt Kingtronics offer size from 0402, 0603, 0805, 1206, 1210, 1808, 1812, 2210, 2225, voltage from 10V to 5000V, dielectric materials include NPO, X7R, Y5V.


  • A wide selection of sizes is available
  • High capacitance in given case size.
  • Capacitor with lead-free termination (pure Tin).


  • For general digital circuit.
  • For power supply bypass capacitors.
  • For consumer electronics.
  • For telecommunication.

We supply various electronic components and welcome your inquiry

The capability of the surge arrester in energy dissipation against switching surge is well expressed by the magnitude of kJ/kV (arrester rated voltage). These values show the dissipated total energy per two shots of switching surge that the surge arresters can withstand thermally with these values. Where the energy capability is inadequate in our standard series.

Typical structure of surge arresters are shown in Figure below .The surge arresters are basically composed of the TNR elements, housing and associated parts with insulating gas filling as shown in figures. The hermetic sealing of the housing is constructed with weather-proof synthetic rubber. The pressure relief diaphragm is structured with special metal plate, which is ruptured when a sudden pressure rise occurs in case of the internal failure.

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.

1.Large capacitance to volume ratio, smaller size, good stability, wide operating temperature range, long reliable operating life.

2.Extensively used in miniaturized equipment and computers. Available in both polarized and un polarized varieties.

3.Solid tantalum capacitors have much better characteristics than their wet counterparts.

A membrane potentiometer uses a conductive membrane that is deformed by a sliding element to contact a resistor voltage divider. Linearity can range from 0.5% to 5% depending on the material, design and manufacturing process. The repeat accuracy is typically between 0.1mm and 1.0mm with a theoretically infinite resolution. The service life of these types of potentiometers is typically 1 million to 20 million cycles depending on the materials used during manufacturing and the actuation method; contact and contactless (magnetic) methods are available. Many different material variations are available such as PET(foil), FR4, and Kapton. Membrane potentiometer manuafacturers offer linear, rotary, and application-specific variations. The linear versions can range from 9mm to 1000mm in length and the rotary versions range from 0° to 360°(multi-turn), with each having a height of 0.5mm. Membrane potentiometers can be used for position sensing.http://www.kingtronics.com/trimming-potentiometers/

This circuit's operation is easily understood one half-cycle at a time. Consider the first half-cycle, when the source voltage polarity is positive (+) on top and negative (-) on bottom. At this time, only the top diode is conducting; the bottom diode is blocking current, and the load “sees” the first half of the sine wave, positive on top and negative on bottom. Only the top half of the transformer's secondary winding carries current during this half-cycle as in Figure below.

This is a measure of a capacitor's ability to store charge. A large capacitance means that more charge can be stored. Capacitance is measured in farads, symbol F. However 1F is very large, so prefixes are used to show the smaller values.

Three prefixes (multipliers) are used, ?? (micro), n (nano) and p (pico):

?? means 10-6 (millionth), so 1000000??F = 1F
n means 10-9 (thousand-millionth), so 1000nF = 1??F
p means 10-12 (million-millionth), so 1000pF = 1nF
Capacitor values can be very difficult to find because there are many types of capacitor with different labelling systems!

Contact us

Tel: (86) 769 8118 8110
Tel: (852) 8106 7033
Fax: (852) 8106 7099
E-mail: info@kingtronics.com
Skype: kingtronics.sales
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Web: www.Kingtronics.com


Kingtronics International Company was established in 1995 located in Dongguan City of China to handle all sales & marketing for factories located in Chengdu, Sichuan and Zhaoqing, Guangdong, China. In 1990, we established the first factory to produce trimming potentiometer and in 1999 we built up new factory in Zhao Qing, Guangdong. Now with around 850 workers, Kingtronics produce trimming potentiometers, dipped tantalum capacitors, multilayer ceramic capacitors, and diode & bridge rectifier. We sell good quality under our brand Kingtronics, and Kt, King, Kingtronics are our three trademarks. All our products are RoHS compliant, and our bridge rectifier have UL approval. Please visit our Products page, you could please download all our PDF datasheet and find cross reference for our Trimming Potentiometer and capacitors.

Tantalum and Ceramic Capacitors Cross Reference ↓ Download
Diodes & Rectifiers List(PDF: 97KB) ↓ Download
Trimming Potentiometer Cross Reference ↓Download

Meet Kingtronics in Moscow soon
Convention and Exhibition Centre,HongKong
Date: 13-16 October, 2019
Booth No.: 5G-C26

Meet Kingtronics in Munich soon
New Munich Trade Fair Centre, Germany
Date: 10-13 November, 2020
Booth No.: To be advised



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