Electronic Capacitor Distributor in China
- Used in controllable or adjustable AC power systems with rated voltages up to 3.6 kV and frequencies of 50 kHz and below.
- Features high temperature and low impedance.
- Rated for automotive applications, as well as SMD technology.
- Comes with non-solid electrolyte, self-healing SMD-version with base plate, lead free reflow solderable.
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Reputed Electronic Capacitor Supplier - Rantle East Electronic
RANTLE Electronic Capacitors are mainly used in controllable or adjustable AC power systems with rated voltages up to 3.6 kV and frequencies of 50 kHz and below. It is specifically designed to improve the power factor of induction heating, melting, stirring, or casting devices and similar applications.
RANTLE Electronic Capacitor is also used for start and run and are available in plastic case and in metallic case for safety protection of your devices. The electrodes consist of an extremely thin metal coating obtained by vacuum evaporation. The case and cover are made with self-extinguishing plastic material, the capacitive element sealed with polyurethane resin.
RANTLE Electronic Capacitor features high temperature and low impedance. They are charge and discharge proof, and the 4-pin and 6-pin versions are vibration proof. Electronic capacitors are rated for automotive applications, as well as SMD technology where high temperature reflow soldering is used. Other applications include industrial, telecom, smoothing, filtering, and buffering. Installation place no violent mechanical vibration, no harmful gases and vapors, conductivity and explosive dust.
Furthermore, RANTLE Electronic Capacitor are also designed for audio applications. Electronic Capacitor comes with non-solid electrolyte, self-healing SMD-version with base plate, lead free reflow solderable. The plates are stacked by hand to the required value, have their edges reinforced with silver paste and then sintered at 560°C.
RANTLE is an independent electronic capacitor distributor for almost 15 years. We provide high-quality parts, competitive price, swift delivery, quality service, good reputation and global sourcing network. Our quality control team is working hard to ensure the quality of all parts of electronic capacitor we are selling. We provide 30 days warranty so you have nothing to worry about. Our inventory is maintained to the highest standards in our controlled environment warehousing facility. Feel free to contact with us today.
Electronic Capacitor: The Ultimate FAQ Guide
In this guide, you will find answers to any question you may have about the electronic capacitor.
Whether you want to learn about components, design, working principle, classification, or quality testing, all the answers are here.
Take a look:
- What is an Electronic Capacitor?
- What is the Difference between a Battery and Electronic Capacitor?
- What is the Function of Electronic Capacitor?
- How is an Electronic Capacitor Constructed?
- How does an Electronic Capacitor Work?
- How are Electronic Capacitors Connected?
- What is Capacitance?
- How is an Electronic Capacitor Charged?
- What Liquid is inside an Electronic Capacitor?
- How are Electronic Capacitors Classified?
- How many Types of Electronic Capacitors are there?
- Where are Electronic Capacitors used?
- What are Electronic Capacitor Specifications?
- What is the Difference between Electronic Capacitor and Inductor?
- How Long can an Electronic Capacitor Function?
- What is a Voltage-controlled Capacitor?
- What are the Characteristics of Electronic Capacitors?
- How do you Test an Electronic Capacitor?
- What are Ultra-capacitors?
What is an Electronic Capacitor?
Am electronic capacitor is a passive device with a terminal pair that uses an electrical field to store electrical energy.
A passive device is one able to derive its power from a circuit and store it.
An electronic capacitor consists of two conductive plates separated by an insulator.
The voltage applied to a capacitor determines the amount of charge it can hold.
Therefore, the higher the voltage applied, the higher the charge it can hold.
This amount of charge consequently determines its capacitance.
What is the Difference between a Battery and Electronic Capacitor?
A battery is used to supply energy in the form of direct current to an electrical circuit.
It has a positive and negative terminal with an enclosed compartment containing an electrolyte that stores charge.
A battery is charged through chemical reactions in the electrolyte which produces useful voltage.
The capacitor differs majorly from the battery by the form in which the electrical charge is stored.
A capacitor stores its energy as an electric field whereas energy in a battery is in chemical form.
What is the Function of Electronic Capacitor?
An electronic capacitor primarily works to store an electrical charge that could be harnessed to serve some other function in a circuit.
A capacitor is charged on the application of a voltage source.
It utilizes the current flow to build an electric field that forms around its conductive plates.
This electric field creates a potential difference in which the electronic capacitor will convert into electrical energy when called upon.
How is an Electronic Capacitor Constructed?
The construction of a capacitor is quite simple as you will establish.
It is an assembly of a pair of conductive plates enclosing a layer of non-conductive material.
The non-conductive material is referred to as a dielectric.
Also, the conductive plates are parallel to each other, and the dielectric layer between them prevents them from contacting.
Materials that are insulators are used as dielectric and include plastic, rubber, ceramic, or glass among many others.
The conductive plates are usually metals with excellent conductivity properties such as aluminum.
Parts of electronic capacitor
The amount of charge a given capacitor can hold is dependent on the way it is constructed.
Besides, the connecting wires or leads are attached to each conductive plate.
When the conductive plates are more extensive, a capacitor stores more charge.
Additionally, when the distance between the plates is great, the capacitor’s charge storage ability reduces.
The quality of the dielectric will also influence the charge storage ability.
How does an Electronic Capacitor Work?
When a capacitor is connected in a circuit and current allowed to flow, the conductive plates receive a charge.
This charge is prevented from flowing further by the dielectric between the plates.
Negative charges coalesce on a plate trapped by the insulator assigning it to the negative terminal.
Since electrons attract unlike charges, there is a build-up of positive charges across at the other conductive plate.
The presence of charges of opposite polarity at the plates creates an electric field.
Despite the strong action of attraction, the charges cannot move due to the dielectric presence, which is an insulator.
You find that the thinner the dielectric, the stronger the electric field.
It is this electric field that determines the charge level in a capacitor.
Thus, a capacitor allows these trapped charges to flow when connected in a circuit as a source of electrical charge. Thus, the capacitor discharges.
How are Electronic Capacitors Connected?
Connecting capacitors in parallel
Connecting capacitors in series
You find electronic capacitors can be connected in two ways: parallel or series.
When capacitors are connected in series, they are successively connected in a similar path.
In this manner, you find that all the capacitors experience a similar amount of the flow of charge.
As such, the charge flow through the first capacitor is the same for every other capacitor.
To get the total capacitance of a series connection, you first establish the capacitance reciprocals of individual capacitors.
You then sum them up. Finally, you establish the reciprocal of the obtained sum.
A parallel connection of capacitors creates diverse paths for every capacitor in the network. This way, different charge levels flow through each capacitor.
The amount of charge flow in a capacitor will be directly related to its capacitance.
The total capacitance is found by totaling individual capacitor capacitance.
What is Capacitance?
Capacitance is a unit of measure describing how much charge a capacitor can hold at a given voltage.
The unit of measuring capacitance is the Farad, which is a large unit.
Consequently, you find capacitance quoted in smaller variants of the Farad such as the microfarad and picofarad.
How is an Electronic Capacitor Charged?
An electronic capacitor is charged by connecting it to a voltage source that allows an electrical charge to flow.
The positive terminal of the electrical source is connected to a conductive plate and the negative terminal to the other plate.
When current flows, it upsets the charge neutrality at the plates.
The plate connected to the negative terminal will accumulate negative charges repelling the positive charges at the plate.
A build-up of the opposite charge occurs at the other plate.
Accumulation of the charges at the plates creates an electric field that cannot be broken.
This is because of the dielectric layer, which is not conducive.
Also, this way a capacitor is said to be charged.
What Liquid is inside an Electronic Capacitor?
The liquid inside an electronic capacitor is specific to the electrolytic capacitor.
Also, the electrolytic capacitor is a polarized capacitor type that utilizes an electrolyte for a cathode rather than a conductive plate.
The electrolyte typically looks like a paste and is ionized.
This means it can hold and carry an electrical charge.
How are Electronic Capacitors Classified?
You find electronic capacitors in virtually every industrial application.
Capacitors find use in consumer electronics, in the telecommunication industry, the automotive industry, and many others.
As such, you find capacitors are constructed to serve different purposes.
With this in mind, you find a myriad of capacitor types each serving a different purpose to which its best suited.
However, all these capacitors have some common characteristics that could be used to organize them in fewer distinct groups.
Electronic capacitors can be classified as follows.
· Variable and Fixed Capacitor
A capacitor can be described as fixed or variable alluding to the ability to adjust the capacitor.
A variable capacitor can be adjusted to vary its charge storing capacity.
Such a capacitor can have a knob that can be used to modify the capacitor or a screw.
Besides, a variable capacitor with a knob can be adjusted while in use.
A recognizable application for this capacitor is a transistor radio.
In this application, it is used to surf between channels and in fine-tuning.
A variable capacitor can also have a screw that is used to cascade through preset levels. Such a capacitor can only be adjusted when not in immediate use.
This way, it can only be altered when it is to be operationalized or when it is being tested.
Fixed capacitors cannot be modified, and the manufacturer sets its properties.
Many capacitors are fixed, which their identifying elements stipulated by the manufacturers. When you desire an improved charge storing ability, you have to replace them.
· Polarized or Non-Polarized Capacitors
polarized and non-polarized capacitor
Polarization refers to the setting of distinct terminals on an electronic component as either positive or negative.
When a capacitor is polarized, it means it has a designated positive and negative terminal. These terminals have to adhere when connecting them in the circuit.
Disregarding the capacitor’s polarization could result in their damage in the circuit.
A non-polarized electronic capacitor has no particular positive or negative terminal.
Such a capacitor can be connected in whatever manner in an electrical circuit without fear of damage to it.
A ceramic capacitor is a suitable example of a non-polarized capacitor.
· Leaded and Surface Mount Capacitors
A leaded capacitor is a capacitor with leads.
Leads are those two protruding wire extensions on capacitors. Leads are used to fix capacitors in a circuit.
Many capacitors are leaded.
Surface mount capacitors lack leads. As such, the only way to fix them in circuitry is by soldering them to the circuit board.
Soldering is a heat-intensive process, and such capacitors should be capable of enduring the temperature conditions.
Surface mount capacitor
Only a few capacitors are of this type and include ceramic capacitors.
Ceramic capacitors are made of ceramic material which is a poor heat conductor with a very high melting point.
· Classification Based on the Dielectric used
The dielectric is the insulating layer found between the two conductive plates in the construction of a capacitor.
Any material that cannot conduct electricity can be used as a dielectric.
Common materials used include glass, ceramic, plastic, and rubber.
You can classify capacitors basing on the type of dielectric used.
This way you can have capacitors employing rubber as the dielectric, capacitors employing ceramic as a dielectric, and so forth.
How many Types of Electronic Capacitors are there?
You find several types of electronic capacitors used in different circuits.
These capacitors have different values for capacitance, indicating different storage abilities. Some electronic capacitors that you will find include the following:
· Ceramic Capacitor
Ceramic capacitors have ceramic-based dielectric as their name suggests.
This capacitor type is non-polarized and admired for its performance levels, including at most frequency levels.
You find this capacitor is used for low capacitance in the range of picofarads to a microfarad.
With ceramic capacitors, you can achieve a decent stability level and a reduced factor for charge loss.
Additionally, the type of ceramic material that you use determines to what extent you will derive the most of these abilities.
There are two types of ceramic capacitors you can find: multilayer ceramic capacitors and disc ceramic capacitors.
· Disc Ceramic Capacitor
Disc ceramic capacitor
This ceramic capacitor is disc-shaped and leaded. It is fabricated by overlaying the ceramic with point contacts made of silver.
It is then coated with a protective layer to guard against physical damage and degradation.
Disc ceramic capacitors have a higher capacitance than multilayer ceramic capacitors. Additionally, they find use in applications requiring high-frequency levels.
· Multilayer Ceramic Capacitors
Multi-layer ceramic capacitor
Multilayer ceramic capacitors are surface mounted.
Their construction involves the agglomeration of multiple layers parallel to each other.
The contact point for the multilayer ceramic capacitor is designed to allow it to be soldered easily to the circuit board.
Also, the soldering process generates a lot of heat.
Moreover, the multilayer ceramic capacitor is coated with a reinforced polymer to allow protection from the high-temperature conditions.
Besides, it also protects this capacitor from physical injury.
You find multilayer ceramic capacitors are highly employed in electronic devices where they are used in large numbers.
A major drawback for the ceramic capacitors is their reduced ability to store charge compared to polarized capacitors.
However, ceramic capacitors have a few advantages over other capacitor types as identified.
- You will find ceramic capacitors that are both surface mounted and with leads.
- Their ability to be mass-produced makes them cheap to manufacture.
- Ceramic capacitors provide excellent stability which is influenced by the dielectric used.
- Their performance in application requiring high frequencies is admirable.
· The Electrolytic Capacitor
The electrolytic capacitor is a polarized capacitor that substitutes one of the conductive plates that is usually a metal, for an electrolyte.
The modification allows the electrolytic capacitor to store large capacitance values up to thousands of microfarads.
An electrolyte is a chemical solution with the capability of carrying an electrical charge.
For an electrolytic capacitor, the electrolyte takes semi-liquid form as a jelly-like paste.
Usually, this forms the negative terminal while the metal plate forms the positive terminal.
The electrolyte capacitor’s dielectric made of an insulating oxide layer and is very thin.
This size allows the electrodes to be closer together, enabling the capacitance to be very large. Wrongful connection of the terminals results in permanent damage to the capacitor.
You find electrolytic capacitors with the following features that are useful when handling these capacitors in circuits.
- Electrolytic capacitors cannot be relied upon in high-frequency applications.
This is because at higher frequencies, the equivalent series resistance of the electrolytic capacitor increases.
- You find the large value capacitance allows electrolytic capacitors to be employed in circuits with a direct current source.
This way, when utilized in applications involving coupling and decoupling, they minimize the occurrence of ripple currents.
- Circuits employing such capacitors have high currents and consequently, high equivalent series resistance.
You need to establish an electrolytic capacitor’s ability to overcome the ESR to supply the required current amount.
- Electrolytic capacitors have a broad tolerance range.
As such, they are not suitable for use in circuitry requiring narrow tolerance range or specific capacitance value requirements.
- You need to watch out for leakage with the electrolytic capacitor. This is especially true for sensitive applications such as when used in circuits for input devices.
- It is essential to determine the ripple current anticipated when using electrolytic capacitors in high current applications.
Otherwise, if large enough, it can damage the capacitor.
Most electrolytic capacitors provide details relating to their capacitance, operating temperature, and voltage on their surface.
Sometimes, other specific details are included for information such as the ripple current value.
There are two variations of the electrolytic capacitor: tantalum electrolytic capacitor and an aluminium electrolytic capacitor.
· Tantalum Electrolytic Capacitors
The tantalum electrolytic capacitor finds two forms with one utilizing a wet electrolytic type and the other a dry/solid one.
The dry tantalum electrolytic capacitor utilizes the oxide of manganese as the cathode and is more popular.
Compared to an aluminum electrolytic capacitor, the tantalum capacitor uses dielectrics that provide superior capacitance.
Additionally, the tantalum capacitor exhibits lesser leakage of currents allowing their use in applications such as decoupling and timing.
Tantalum electrolytic capacitors can bear reverse polarization given their low operating voltages. This enabled the engineering of a tantalum electrolytic capacitor to be non-polarized.
Such capacitors are used where the direct current voltage is larger than the alternating current voltage.
· Aluminum Electrolytic Capacitors
The aluminum electrolytic capacitor also finds two forms: the plain foil and etched foil.
Also, the etched foil differs from the plain foil by the patterning of the foil.
The etched foil, therefore, increases in surface area the ability to create and store a larger electrical field.
Etched foil aluminum electrolytic capacitors find use in applications requiring higher capacitance values such as blocking direct current and coupling.
Foil type aluminum capacitors find use in applications with lower requirements such as smoothing operations.
A direct current is set to the aluminum electrolytic capacitor to enable polarization.
Utilizing an aluminum film as an electrode, this capacitor experiences a voltage breakdown at a high value.
This allows the capacitor to store more capacitance despite its larger size.
As polarized devices, altering the lead placement in a circuit could destroy the dielectric.
The impairment in an aluminum electrolytic capacitor is, however, reduced due to the electrolyte presence.
Besides, the efficiency of an aluminum electrolyte capacitor reduces over time as the electrolyte dries out.
Also, the layer of oxide that forms on the positive electrode also wears off requiring repolarization.
To maintain an aluminum electrolytic capacitor, you have to maintain its use within its current and voltage limits.
Additionally, even though they can endure reverse voltages, you should avoid that. Furthermore, it is best to operate the capacitor within normal temperature conditions.
Even though you find most electrolytic capacitors are leaded, there are some surface-mounted electrolytic capacitors.
These come at low cost and with admirable capacitance levels.
The use of surface-mounted electrolytic capacitor has blossomed due to new less abrasive soldering techniques.
Information on the capacitance and a working voltage of a surface mount electrolytic capacitor are provided on the component.
You find the manufacturing cost of electrolytic capacitors is low, making them affordable.
Moreover, they have large capacitance values in comparison to other capacitor types of similar size.
The electrolytic capacitor is, however, handicapped in the following ways:
- Electrolytic capacitors have a large tolerance range and are unreliable in circuit’s requiring specific capacitance values.
- These capacitors are prone to leakage currents which could be damaging when used in circuits for input devices.
- They are not suitable for high-frequency applications due to their high equivalent series resistance.
- The voltage rating of electrolytic capacitors is low, making them unsuitable for use in circuits supplying alternating current.
- Compared with other electronic capacitors, you find the electrolytic capacitors have a shorter lifespan.
· Film Capacitors
Film capacitors are capacitor types that have the electrodes and dielectrics drawn out into films and coiled together.
Many different materials can be used as the dielectric providing many types of film capacitors. Thus, you find film capacitors are the most common capacitor types.
Some film capacitor types utilize plastic dielectric hence the name plastic capacitors.
Such capacitors can function reliably in high-temperature conditions providing an extended service life.
Besides, their tolerance margins are narrow, making them highly dependable.
The many types of film capacitors allow a wide range of capacitance values ranging.
Film capacitors can be categorized according to their construction given the film foil capacitor and metalized film.
The film foil has metal foils of minimal thickness sandwiched by a dielectric and rolled up together.
Besides, the electrode terminals are attached by soldering or welding.
They are then packaged in paper or cylindrical metal casing.
With the metalized film design, the electrode films are deposited with a layer of granular metallic particles on both sides.
This allows the electrodes the ability to recover conductive properties when one side wears out.
It also allows higher values for capacitance.
Some film capacitor types include:
· Polyester Capacitor
This capacitor utilizes a polyester dielectric and can be made with both film foil and metalized film construction.
Their high-temperature rating of over a hundred degrees Celsius allows for production as surface-mounted capacitors.
Polyester capacitors are small in size with a capacitance of less than a microfarad.
Also, they are cheap and find use in general applications requiring capacitors.
They, however, produce noise sounds when used in applications with vibrations.
· Polythene Sulphide Capacitors
Using polythene sulfide as a dielectric, this film capacitor type is only constructed in the metalized foil design.
They find use in instances where there is a need for constant frequency and elevated temperatures. They can also be fabricated to be surface mounted.
· Polyethylene Naphthalate Capacitors
The polyethylene naphthalate capacitor is only available in metalized film configuration.
It has a high operating temperature rating with desirable performance.
This allows their use as surface mounts.
They are large in size with a high voltage rating finding use in coupling applications.
· Polytetrafluoroethylene Capacitors
The foil film design and metalized film design can be used for this film capacitor type.
It has a distinctively high working temperature rating of over 200°C.
However, its tolerance margin is broad and costs an arm and a leg reducing their usage.
· Silver Mica Capacitor
The silver mica capacitor type is a reinvention of the earlier highly unstable mica capacitor that utilized a mica dielectric.
This capacitor improves on the mica dielectric by depositing silver on the mica to form the conductive electrodes.
The silver mica capacitor has a high working temperature rating with narrow tolerance margins offering superior performance levels.
Additionally, the voltage applied to them has minimal influence on its capacitance. They are mostly leaded, albeit some are surface mounts.
Silver mica capacitors find use as signal filters due to their narrow tolerance range.
They are also used as radiofrequency oscillators with their low energy loss.
Additionally, they can also be used in transmitters and amplifiers due to their ability to output high voltage values.
You find silver mica capacitors preferred for the following;
- They are available in a wide capacitance range of a few picofarads to a couple of thousands.
- Their capacitance is also minimally affected by voltage.
- They have a high working voltage rating of up to a kilovolt.
- Silver mica capacitors exhibit reduced charge loss.
- Their tolerance margin is narrow, allowing use in application requiring specific capacitance values.
- The level of a silver mica capacitor’s temperature coefficient is low.
There are certain limitations to the silver mica capacitor. You find that they are large in size and prohibitively expensive.
Additionally, they are limited as surface mountable and sometimes exhibit fluctuating values when used.
Where are Electronic Capacitors used?
Electronic capacitors have found a myriad of uses across industries employing electrical circuits. Some of the primary uses are as follows.
Capacitor in speakers
You find the electronic capacitor is employed to change alternating current into direct current. This allows its use in converting current for electronic appliances requiring direct current for operation.
The capacitance of an electronic capacitor varies with the dielectric composition, plate surface area and the plate distance.
As such, altering the composition of the dielectric and varying the distance between plates can be used for sensory applications.
Smoke signals utilize capacitors with a porous dielectric to determine the presence of smoke particles in the air.
Furthermore, fuel gauges in airplanes utilize the plate area to determine fuel levels.
Plate distance can be used to create sensors for determining pressure.
For example, fingerprint sensors.
Electronic capacitors are able to charge and discharge at distinct intermissions.
You can, therefore, use electronic capacitors in applications requiring timed responses.
For example, an electronic capacitor could be used in a flashing signal in a lighthouse.
The start and run capacitors are important in the operation of the single-phase motor.
Besides, the start capacitor is useful in ensuring the initialization of motor rotation.
The run capacitor is used to enhance the charge required for a motor to power and operate efficiently.
Variable electronic capacitors are employed in radios to facilitate the tuning process.
By a charging and discharging process, the capacitor is able to align with radio frequencies allowing you to catch signals.
Capacitors store electrical energy in the form of charge.
This happens when you connect an electronic capacitor to a circuit with a voltage source.
You can harness the stored energy for some other purpose. In memory chips, capacitors are used to hold a charge for the chips.
Electronic capacitors fins use as high-pass, low-pass, and noise filters.
A filter is an electrical device that filters out signals based on a defined threshold frequency.
For a high-pass filter, signals above the threshold frequency are allowed, and those below are blocked.
The low-pass filter works in the same way.
What are Electronic Capacitor Specifications?
Capacitor specifications can be described as distinguishing factors inscribed on a capacitor to help you identify their properties.
These specifications include:
Polarization refers to the assignment of leads with positive and negative identification that help you when connecting electrical components.
Some capacitors are polarized and as such highlight a way of identifying which is the positive or negative terminal.
A capacitor has a capacitance value indicated on it.
However, when you measure the capacitance amount, it usually is not the exact figure as indicated.
Tolerance is provided as a percentage highlighting how close the actual capacitance amount is to the indicated amount.
This is the amount of charge that a capacitor can store at a certain voltage. It is measured in Farads usually given in smaller units of microfarads or picofarads.
iv. Breakdown Voltage
This highlights the voltage amount at which breakdown in capacitance occurs.
The breakdown is a point where the capacitor cannot hold onto charge resulting in an incomplete circuit.
What is the Difference between Electronic Capacitor and Inductor?
An inductor is a passive device just like the electronic capacitor.
It is designed like a coil and uses a magnetic field to store energy.
Current flow through the coil creates a magnetic effect that influences a voltage.
You find the way energy is stored in the inductor is different from an electronic capacitor.
An inductor utilizes a magnetic field for energy storage, and an electronic capacitor uses an electric field.
An electronic capacitor prevents the flow of current through it by the presence of the dielectric layer.
Contrarily, an inductor allows current to flow through its coil as the magnetic field is created this way.
Additionally, you find that while a capacitor bocks direct current, inductors allow the flow of direct current.
How Long can an Electronic Capacitor Function?
An electronic capacitor can function for a long time, up to tens of years, when operated at the rated characteristic conditions.
Operating conditions such as temperature can affect the working of capacitors.
Very high and low temperatures will lead to eventual capacitor failure.
Additionally, subjecting the electronic capacitor to voltages higher than the working voltage will surely reduce the capacitor’s life.
Furthermore, connecting the capacitors with reverse polarity is a quick way of shortening an electronic capacitor’s lifespan.
What is a Voltage-controlled Capacitor?
A voltage-controlled capacitor is another name for a varactor or varicap.
It is a two-terminal device that allows unidirectional current flow. It works when a p-n junction is reverse biased capitalizing on the capacitance that is controlled by a voltage input.
What are the Characteristics of Electronic Capacitors?
Electronic capacitor characteristics are information bits related to the capacitor and its operation, generally provided by the manufacturer.
· Nominal Capacitance
This capacitor characteristic provides the amount of charge that a given capacitor is expected to hold at a provided voltage.
Its measurement unit is the Farad provided in smaller variants: microfarads or picofarads.
Capacitance can be affected by temperature and frequency.
It is indicated on the surface of the capacitor as a numeric value. A tolerance level usually accompanies the value.
· Leakage Current
The dielectric material placed between the conductive plates of a capacitor could allow a reduced current flow.
This occurrence can be attributed to their imperfect insulator property that gets overwhelmed under strong electric field presence.
This way, a few charges manage to escape the plates into the dielectric. This constitutes the leakage current.
You find electrolytic capacitors post the highest value of leakage resistance while foil capacitors are at the opposite end.
Leakage current is not usually large and is usually in the range of nano-amperes.
Electronic capacitors with high leakage current cannot be used in storage applications and also coupling.
· Operating Temperature
Dielectrics in electronic capacitors are easily affected by temperature conditions.
Since the role dielectric plays in a capacitor is very important, such changes will affect its performance.
Electronic capacitors, therefore, need to be operated within certain temperature margins that are not too low or too high. The temperature values are provided in degrees Celsius or degrees Fahrenheit.
Tolerance describes the range with which the actual capacitance can vary either over or under with the rated nominal capacitance.
It is expressed in the same units as capacitance, the Farad.
For example, the nominal capacitance could be given as fifty microfarads and the tolerance value as 20.
This is interpreted as the capacitance could actually be 70 microfarads or 30 microfarads.
Tolerance could also be expressed as a percentage.
This percentage is referenced to the capacitance.
Consider a capacitor with a fifty microfarad capacitance rating and a ten percent tolerance.
The actual tolerance is ten percent of fifty, which is five microfarads.
· Operating Voltage
This characteristic provides the voltage amount that a capacitor needs be subjected to, to ensure proper operability.
It is usually associated with the direct current voltage and is subject to optimum working temperature range.
This voltage amount is indicated on the face of the capacitor in volts.
Exceeding the working voltage may result in the catastrophic failure of the electronic capacitor.
· Equivalent Series Resistance
Equivalent series resistance is a summation of exhibited resistances pronounced at various points of a functioning capacitor.
It includes the resistance an electronic capacitor exhibits against alternating current signals when in a high-frequency environment.
Additionally, it encompasses the dielectric resistance and the resistance to the direct current of the conductive plates and leads.
All these are when the electronic capacitor is subjected to increased frequency and temperature levels.
The ESR value is provided in ohms.
Electronic capacitors with low ESR values find use in signal filtering applications.
How do you Test an Electronic Capacitor?
You will find a number of doing it yourself ways to test a capacitor.
You need to ensure the capacitor is discharged before carrying out a test.
Additionally, in the case of polarized electronic capacitors, you need to adhere to the proper terminal connection.
One straight forward method to test a capacitor is to use a capacitance meter.
A capacitance meter measures the capacitance level in an electronic capacitor.
You attach the meter leads to the capacitor terminals and tread the capacitance value on the meter.
The value should be within the tolerance range of the capacitor. Otherwise, the capacitor is defective.
You can also use a multimeter to establish whether an electronic capacitor is functioning or not. An analog multimeter is preferable as the deflection of the meter hand indicates changes.
By using the meter’s battery, this test charges the capacitor and responds through deflecting.
You first set the multimeter so it can present high values in ohms.
Then connect the multimeter to the capacitor.
This should reflect on the multimeter display by the movement of the hand. It should move from the zero markers towards the highest value where it continuously defects.
Movement indicates a charging capacitor which is a good sign of approval.
However, a malfunctioned capacitor will incite no response form the multimeter with the hand stuck at the zero markers.
This means it does not accept a charge from the multimeter battery.
Besides these tests, you can carry out a test to establish the voltage presence in a capacitor.
Electronic capacitors store voltage and usually have a rated working voltage provided on their casing.
To carry out this test, you connect an electronic capacitor to a battery source.
This battery should have a lower voltage than the capacitor’s operating voltage.
Disconnect after a few seconds and connect the capacitor to a multimeter.
The voltage reading in the multimeter should be equal to the voltage of the battery for a good electronic capacitor.
It should then quickly discharge to zero. A faulty electronic capacitor’s voltage reading does not match that of the battery source.
What are Ultra-capacitors?
Ultra-capacitors, otherwise known as supercapacitors, are an improved development of the electronic capacitor.
These capacitors leverage on high conductive surface area and very thin dielectric to achieve higher values of capacitance.
This way, they are able to store up to thousands of Farads.
Construction of ultra-capacitor
Ultra-capacitors are composed of a pair of two-sided carbon electrodes separated by a porous membrane called a separator.
The electrodes and separator are infused with a semi-liquid electrolyte and separated by an aluminum foil for collecting current.
This construction with a double layer lends the alternative name of the double-layer capacitor to the ultra-capacitor.
Additionally, this construction allows the creation of a surface area in the zone of thousands of meters square.
This is by rolling the assembly in a coil.
When an ultra-capacitor is connected to a voltage source, the electrodes attract charges with opposite polarity.
The separator allows the passage of smaller positive charges restricting the electrons on the other side.
Carbon is preferred as it does not react with the electrolyte improving capacitor performance.
Additionally, as ultra-capacitors use low voltage amounts, the ions do not undergo oxidation or reduction as in an electrolytic capacitor.
The large surface area allows the entrapment of many charges in an electric field.
This speaks to the ability of ultra-capacitors to achieve high capacitance values.
As such, these capacitors find use as storage devices for electrical energy.
However, the ultra-capacitor has a low terminal voltage which is its major drawback.
You, therefore, need many ultra-capacitors connected in series to achieve a higher voltage value.
When in need of a larger capacitance value, a parallel connection of ultra-capacitors will suffice.
Research is ongoing to use ultra-capacitors as the green energy source in the automotive industry, much like batteries.
With the information in this guide, you can definitely choose high quality electronic capacitor.
However, if you have more questions on the electronic capacitor or memory ICs, Rantle team is here to help.