Suntan Blog

Zener diodes are manufactured with zener voltages ranging anywhere from a few volts to hundreds of volts. This zener voltage changes slightly with temperature, and like common carbon-composition resistor values, may be anywhere from 5 percent to 10 percent in error from the manufacturer's specifications. However, this stability and accuracy is generally good enough for the zener diode to be used as a voltage regulator device in common power supply circuit in Figure below.

Capacitance is the ability to store electric charge. In its simplest form a capacitor consists of two parallel plates or electrodes that are separated from each other by an insulating dielectric. It is found that when a battery or any other voltage source is connected to the two plates as shown a current flows for a short time as it charges up. It is found that one plate of the capacitor receives an excess of electrons, while the other has too few. In this way the capacitor plate or electrode with the excess of electrons becomes negatively charged, while the capacitor electrode becomes positively charged.

If the battery is removed the capacitor will retain its charge. However if a resistor is placed across the plates, a current will flow in the resistor until the capacitor becomes discharged.

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

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

b. Frequency

c. 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.

d. 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.

e. 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.

f. 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 .

Suntan Technology Company Limited will attend Electronic Americas 2011 in Sao Paulo, Brazil from March 28th to April 1st, 2011

• Fair name: Electronic Americas 2011
• Add.: Sao Paulo, Brazil
• Date: March 28th to April 1st, 2011
• Booth No.:N₁50

On this exhibition, all products will be presented, like metalized polyester/ polypropylene film capacitor including X2 capacitor, MLCC and high voltage ceramic capacitor, aluminum electrolytic capacitor, trimming potentiometer, varistor and rectifier diode.

Welcome to visit our booth to establish or expand our business!

Capacitance can be decreased in a circuit by capacitors in series as shown in the following diagram:

We know that capacitance of a capacitor can be decreased by placing the plates further apart. Connecting two or more capacitors in series in effect increases the distance between the plates and thickness of the dielectric, thereby decreasing the amount of capacitance.

The following is the formula for calculating total capacitance in a circuit containing two capacitors in series:
                                                 
CT = (C1 x C2x C3) / (C1 + C2+ C3)

Simple capacitance scales on DMMs just measure the capacitance in uF and do not test for leakage, ESR (Equivalent Series Resistance), or breakdown voltage. If the measurement comes up within a reasonable percentage of the marked value (some capacitors have tolerances that may be as much as +100%/-20% or more), then in many cases, this is all you need to know. However, leakage and ESR frequently change on electrolytic as they age and dry out.

Many capacitance meters don't test anything else but are probably more accurate than a cheap DMM for this purpose. A meter of this type will not guarantee that your capacitor meets all specifications but if it tests bad - very low - the capacitor is bad. This assumes that the test was made with the capacitor removed (at least one lead from the circuit - otherwise other components in parallel can affect the readings.

To more completely characterize a capacitor, you need to test capacitance, leakage, ESR, and breakdown voltage. Other parameters like inductance aren't likely to change on you.

A varistor is an electronic component with a significant non-ohmic current-voltage characteristic. The name is a portmanteau of variable resistor. Resistors are the most widely used components in electronic circuits. Although very simple in concept they are key to the operation of many circuits. They can be used in a variety of ways to produce the required results.

When designing or building an electronic circuit, it may be necessary to use two or more resistors instead of one. Either the correct value of resistor may not be available, or it may be necessary to dissipate a higher power than that which a single resistor can dissipate on its own.

Capacitors may retain a charge long after power is removed from a circuit; this charge can cause dangerous or even potentially fatal shocks or damage connected equipment.  Service procedures for electronic devices usually include instructions to discharge large or high-voltage capacitors. Capacitors may also have built-in discharge resistors to dissipate stored energy to a safe level within a few seconds after power is removed.

Our Suntan has produce a Safety Standard Recognized Capacitor ,It’s specifications is descriped its function detailedly as follows.

Safety Standard Recognized Capacitor - Y Pictures

If you want to have a full knowledge about Safety Standard Recognized Capacitor,please visit  www.suntan.com.hk   and have a view.