Kingtronics Blog

A typical application for high capacitance, high voltage capacitors is a bulk filter capacitor shown in Figure 1 in a bipolar transistor totem pole configuration high voltage, high capacitance MLCCs are commonly used as input capacitor filters.

To obtain the required capacitance and high voltage rating the MLCCs are often placed in parallel or stacked vertically. This requires careful soldering and attachment processing, due to the larger case sizes required for the application. The basic function of the input capacitor filter is to hold up the rectified power bus line voltage as well as for filtering common mode noise.

Common mode noise flows asymmetrically through both input lines. The current into the load is supplied by the input filter capacitor bank rather than from the power supply, until the point at which the input voltage again equals the voltage across the filter capacitor, see wave forms in Figure 2.

A quartz crystal resonator depends on the piezo-electric effect to work. This effect converts a mechanical stress in a crystal to a voltage and vice versa. In this way the piezo-electric effect converts the electrical impulses to mechanical stress which is subject to the very high Q mechanical resonances of the crystal, and this is in turn linked back into the electrical circuit.

The quartz crystal can vibrate in several different ways, and this means that it has several resonances, all on different frequencies. Fortunately the way in which the quartz crystal blank is cut from the original crystal itself can very significantly reduce this. In fact the angle of the faces relative to the original crystal axes determines many of its properties from the way it vibrates to its activity, Q, and its temperature co-efficient. There are three main ways in which a crystal can vibrate: longitudinal mode, low frequency face shear mode, and high frequency shear. A cut known as the AT cut used for most crystals used in traditional radio and electronics circuits uses the high frequency shear mode.

Vibrational modes of a quartz crystal resonator
(For the sake of clarity, the movements have been greatly exaggerated)

A transmission line arrester also known as a transmission line surge arrester is any arrester that is applied out on the transmission line to reduce the possibility.

The resulting wave when an electrical variation in a circuit such as a transmission line takes the form of translation of energy along a conductor, such energy being always equally divided between current and potential forms. The traveling waves propagate at close to the speed of light and can generate surges at 2-4 times the initial impulse under certain circumstances.

Impulse protective levels of an arrester:

a) Fast front protective level: The highest of either the steep current residual voltage or the front-of-wave impulse spark over voltage.

b) Standard lightning impulse protective level: The highest of the residual voltage at nominal current or 1,2/50 lighting impulse spark over voltage.

c) Switching impulse protective level: The highest of either the maximum residual voltage for the specified switching current or the specified switching impulse spark over voltage.

Kingtronics is a manufacturer of Trimming Potentiometer. Trimming potentiometers are Kingtronics' first products. On Kingtronics' trimming potentiometers body, we mark "King" due to insufficient space. “Kingtronics” and "Kt" are our brand too. So, Kingtronics trimmers, Kingtronics potentiometers, King trimmers, and King potentiometers all mean potentiometers which produced by Kingtronics International Company.Our products are well crossed to Bourns Brand parts. We offer Kingtronics potentiometers (with Kt Mark trimming potentiometer) include following part number: RKT-3006, RKT-3266, RKT-3296, RKT-3299, RKT-3323, RKT-3329, RKT-3362, RKT-3386, RKT-3318, RKT-3306, RKT-3309, RKT-065, RKT-105H, RKT-C3305, RKT-3361, RKT-3540S, RKT-3590. Our trimming potentiometers are RoHS compliant.

Now Kingtronics offer Bourns equivalence. If you want more details , please visit website:www.kingtronics.com  for full specification.

If you have any inquiry about Trimming Potentiometer , pls contact info@kingtronics.com.

Welcome to check our price!

Application range:

Peace project(police),telecom "global E-eye"(telecom),road monitoring(police), Community Monitoring(building management), monitoring of environment(environment protection),expressway monitoring, etc.

System specification:

The lightning protection of monitoring system of CCTV is relatively complicated firstly we should understand the main reason why the monitoring system was damaged by the lightning and the possible lightning invaded route, specially, the outdoor monotoring equipment suffer from serious damage of lightning. only analysis on basis of the reason of damage, research and discussion on the laying, shield and earthing mode of signal and power line, the lightning protection device of monitoring system device can be selected and used accurately.

The TV monitoring systemis consisting of three parts as below:

1,The former part: composed of monochrome (colour television) vidicon, len, holder, hood , bracket, etc.

2, transmission part:coaxial-cable,wire,Multi-core wire,fibre,which transmiss video,audio or control signal by way of overhead in air,burial under ground or wall following laying.

3, computer roomterminal part: composed of matrix, monitoring device, hard disk video recorder,etc.

The equivalent series resistance is the resistive element (R1) of the quartz crystal equivalent circuit. (see Equivalent Circuit below) This resistance represents the equivalent impedance of the crystal at natural resonant frequency (series resonance) ESR is measured by a Crystal Impedance (CI) meter.

ESR values are generally stated as maximum values expressed in ohms. The ESR values vary with frequency, mode of operation, holder type, crystal plate size, electrode size, and mounting structure.

It is worth noting that the ESR value at a given frequency for an AT- strip crystal design is generally higher than that of the standard (round blank) design. This becomes more significant at lower frequencies. When transitioning from a series resonant through-hole HC-49/U type crystal to a smaller surface mount type utilizing an AT-strip crystal, some consideration may be given to the difference in the ESR values produced by different cuts.

The ESR becomes critical when resistance values reach a point were the oscillator circuit cannot adequately drive the crystal. Sluggish start-up or unwanted modes of operation may result.

Equivalent Circuit:

The equivalent circuit (shown in Figure A) depicts electrical activity of a quartz crystal unit operating at its natural resonant frequency. The shunt capacitance (Co), represents the capacitance of the crystal electrodes plus the capacitance of the holder and leads. R1, C1, and L1 compose the "motional arm" of the crystal, and are referred to as the motional parameters. The motional inductance (L1) represents the vibrating mass of the crystal unit. The motional capacitance (C1) represents the elasticity of the quartz, and the resistance (R1), represents bulk losses occurring within the quartz.

Schottky rectifiers have been used in the power supply industry for approximately 15 years. During this time, significant fiction as well as fact has been associated with this type of rectifier. The primary assets of Schottky devices are switching speeds approaching zero-time and very low forward voltage drop (VF). This combination makes Schottky barrier rectifiers ideal for the output stages of switching power supplies. On the negative side, Schottky devices are also known for limited high-temperature operation, high leakage and limited voltage range BVR. Though these limitations exist, they are quantifiable and controllable, allowing wide application of these devices in switch mode power supplies.

High leakage, when associated with standard P-N junction rectifiers, usually indicates “badness,” implying poor reliability. In a Schottky device, leakage at high temperature(75 °C and greater) is often on the order to several milliamps, depending on chip size. In the case of Schottky barrier rectifiers, high-temperature leakage and forward voltage drop are controlled by two primary factors: the size of the chip’s active area and the barrier height (φB).

The EKT Series is a high temperature version of Kingtronics's solid tantalum chip family that offers optimal performance in applications with operating temperatures of up to 125° C. Advancements in materials and testing have allowed for the introduction of this series which delivers a reliability level of 0.5% per 1000 hours at rated voltage at rated temperature. This series is available in five standard EIA case sizes with RoHSCompliant/100% matte tin finish lead terminations as standard.

Other termination options include 90Sn/10Pb finishes and gold for conductive adhesive attachment processes. Capacitance values range from . 0.33uF - 470uF, in voltage ratings from 4 to 50 volts.

Kingtronics has developed an innovative construction platform that incorporates multiple capacitor elements,in parallel, inside a single package. This unique assembly, combined with Kingtronics’s superior processing technology, provides the best combination of high CV, low ESR, and small size in a user friendly, molded, surface mount package.

The fundamental electrical properties of multilayer ceramic capacitors are as follows:

Polarity: Multilayer ceramic capacitors are not polar, and may be used with DC voltage applied in either direction.

Rated Voltage: This term refers to the maximum con tinuous DC working voltage permissible across the entire operating temperature range. Multilayer ceramic capacitors are not extremely sensitive to voltage, and brief applications of voltage above rated will not result in immediate failure. However, reliability will be reduced by exposure to sustained voltages above rated.

Like all other practical capacitors, multilayer ceramic capacitors also have resistance and inductance. A simplified schematic for the equivalent circuit is shown in Figure 1. Other significant electrical characteristics resulting from these additional properties are as follows：

Impedance: Since the parallel resistance (Rp) normally very high, the total impedance of the capacitor is ：

The variation of a capacitor’s impedance with frequency determines its effectiveness in many applications.

Quartz crystals used in filters and oscillators in electronic circuits are renowned for their performance, stability, frequency tolerance and their high Q. Yet they do change their frequency very slightly with time in a process known as ageing. Although the frequency variations are small by many standards, they are permanent and may have an effect in some applications where the frequency is of great importance. As a result manufacturing techniques take account of this to reduce the effects of ageing in these crystals as far as possible.

Ageing is caused by a number of interrelated factors. These include internal contamination, excessive drive level, surface change of the crystal, various thermal effects, wire fatigue and frictional wear. The level of ageing can be minimised in a number of ways. During manufacture they should be encapsulated in an inert gas environment, the ensuring should have a good seal so that other gases do not enter. Also the final stages of the preparation of the crystal blank must be prepared as finely as possible. Rather than lapping the blank to bring it to the right dimensions, chemical etching is used. In this way the minimum disruption is caused to the crystal lattice, and this reduces the ingress of contaminants over time that will cause ageing.

The design of the circuit in which the crystal will be used also has an effect. By keeping the drive levels low again the crystal ageing will be less.