Suntan Blog

Tantalum capacitors are manufactured from a powder of pure tantalum metal pressed to form a slug around a tantalum wire and subsequently vacuum sintered at high temperature. The resulting slug, although of high mechanical strength and density, is also highly porous giving a large internal surface area. This forms the positive "plate" of the capacitor. A dielectric layer of tantalum pentoxide is anodized on the surface of the tantalum anode, the cathode is formed by layers of manganese dioxide. Electrical contact is established by the deposition of carbon onto the surface of the "slug". The cathode connection is then made by means of conductive contact to a lead frame. Packaging is carried out to meet individual specification and customer requirements.

There is a great number of different types of circuit that can be used for crystal oscillators, each one having its own advantages and disadvantages. One of the most common circuits used for crystal oscillators is the Colpitts configuration as shown below.

In this configuration, the crystal operates in a parallel mode. When running in this mode, the crystal should be presented with a load capacitance to operate on its correct frequency. This load capacitance is specified with the crystal and is typically 20 or 30 pF. The crystal oscillator circuit will be designed to present this capacitance to the crystal. Most of this will be made up by the two capacitors C1 and C2, although the remaining elements of the circuit will provide some capacitance.

Mica capacitors are typically found in very small capacitance values (less than 100 nF). They will hold a very high voltage static charge, but only a tiny fraction of a joule, and if you handed it to someone they may not even feel the shock from it. If you really want to give someone a good jolt, you should use an electrolytic cap charged up to about 100V. Get one about 10,000 uF. Be careful, because most caps of this size will not be rated for high voltage; they'll explode if you try to charge them much above their rated working voltage.

Don't get too big a cap, or charge it to too high a voltage, because this sort of prank can cause serious burn injury if you take it too far.

Mounting

(1) Do not apply excessive force (preferably 5.0 N max.), when the trimmer capacitor  is mounted on the PCB.
(2) Do not warp and/or bend PCB to prevent trimmer capacitor from breaking.
(3) Use the suitable dimension of the pick-up nozzle (1.1-1.2mm external diameter and 0.8-0.9mm bore diameter).

Cleaning

Cannot be cleaned because of open construction.

Other

Note the polarity of the trimmer capacitor to minimize influence by stray capacitance.
(Refer to the dimensions concerning the polarity.)

Tantalum electrolytic capacitors exploit the tendency of tantalum to form a protective oxide surface layer, using tantalum powder, pressed into a pellet shape, as one "plate" of the capacitor, the oxide as the dielectric, and an electrolytic solution or conductive solid as the other "plate". Because the dielectric layer can be very thin (thinner than the similar layer in, for instance, an aluminium electrolytic capacitor), a high capacitance can be achieved in a small volume. Because of the size and weight advantages, tantalum capacitors are attractive for portable telephones, personal computers, and automotive electronics.

Very low losses, low dielectric absorption, high dielectric strength, very high insulation resistance, and negative temperature coefficient.

Typical applications: Stable oscillators and flters. Sample & hold circuits, pulse handling circuits, AC applications and mains fltering.

Aluminum electrolytic capacitors are made by layering the electrolytic paper between the anode and cathode foils, and then coiling the result. The process of preparing an electrode facing the etched anode foil surface is extremely difficult. Therefore, the opposing electrode is created by filling the structure with an electrolyte. Due to this process, the electrolyte essentially functions as the cathode. The basic functional requirements for the electrolyte are as follows:

(1) Chemically stable when it comes in contact with materials used in the anode, cathode, and electrolytic paper.
(2) Easily wets the surfaces of the electrode.
(3) Electrically conductive.
(4) Has the chemical ability to protect the anode oxide thin film and compensate for any weaknesses therein. 
(5) Low volatility even at high temperatures
(6) Long-term stability and characteristics that take into consideration such things as toxicity.

Tantalum capacitors are a form of electrolytic capacitor. However, some forms of them are non-polar, containing two capacitors connected in series(negative to negative). The conductive polymer manufactured in our unique method is used for the cathode of Tantalum Capacitor, resulting in the reduction of ESR (equivalent series resistance) compared with the conventional manganese dioxide products.

This property of the metal oxide varistor makes it ideal for use in electrical surge protectors. At normal current levels, the MOV will simply pass along the electricity to the devices plugged into the surge protector. In the event of a power surge, however, the MOV will divert the current into itself, preventing it from reaching the attached devices. This will protect sensitive electronic components, such as computer chips, that can be damaged by excessively large voltages. In the event of a sudden power surge, the MOV can respond much more quickly than similar surge-protector components.

A metal oxide varistor is generally made of zinc oxide or a similar substance. These substances give the varistor its quality of passing along current at normal household levels. When electrical current rises to a certain point, called the breakover point or breakover voltage, the tiny zinc oxide particles begin conducting the current among themselves only. This prevents the high-voltage current from passing into the rest of the surge protector or the devices plugged into it.