A complete list of other terms related to Circuit board PCB (VII)

1. Thermal Conductivity

The rate at which a hot substance transfers a given amount of heat through itself.

2, Thermal Mismstch

It refers to two kinds of materials that have been fitted together. Due to the different coefficient of thermal expansion, there will be shear between them after heating, and the underlying cause of separation is buried. If the combination of copper foil and resin substrate is subjected to high heat, once its adhesion is not enough to contend with the force of expansion mismatch, there will be separation or foaming consequences.

3. Thermocouple

It is a temperature measuring device using the principle of "thermoelectric". The combination of two different metal conductors with two contacts will cause the difference in the voltage at both ends of the metal when the temperature rises, and the difference will be proportional to the temperature rise. Therefore, as long as the voltage change at both ends is measured by the voltmeter, the actual temperature of the environment can be expressed. Practically, the two kinds of metal wire can be twisted with the help of small sticks, so that tightly wrapped into a whole, and then cut off the excess end, and after the sealing glue becomes a practical thermocouple.

4, Thermode heating body

Refers to the heat exchanger in direct contact, such as the heat exchanger in the "Hot Bar" welding device.

5. Thermogravimetric Analysis, (TGA)

An analytical method that uses the increase in temperature and the corresponding decrease in the weight of a substance.

6. Three Point Bending test

It is a test method in which the assembled plate is supported by two cross bars from the outside of the lower plate surface, and then pressed down from the third point of the upper center to form a plate bend, and then the strength of each solder joint is observed.

7. Threshold Limit Value(TLV)

Refers to the natural air in the original does not exist substances, through a variety of ways into the air, some of the gaseous substances such as sulfur dioxide, formaldehyde and a variety of dust, harmful to animal and plant ecology. The United States government's "Industrial Hygiene Association "(OSHA), based on the number of hours a day workers are exposed to, has set limits on the amount of hazardous substances in the air, called TLVS. Such as PTH production line site, the TLV of formaldehyde is only 0.7 ppm.

8. Tin Pest

The common white metal tin is called "β tin ", but when the temperature is below 13.2℃, the white tin will gradually change into powdered gray "α tin ", known as "tin epidemic". However, when the temperature rises to 100℃, it will quickly return to β tin.

9. The Topography of the terrain is topography

A Topography is a topography of a hollow slab or assembly, resembling that of the earth. A lateral topography of the same surface is called a Profile.

10, Torsion Strength

"Torsional strength" refers to the maximum torsion force that can be tolerated between the joints of an object or part that has been glued with a binder, when it is intended to be applied to it by twisting force to separate it.

Starting energy Transducer

In ultrasonic cleaning machine, the electric energy into a special component of mechanical kinetic energy, called "energy converter".

12. Translucency is semi-transparent

The property of a material surface that can be partially penetrated or partially exposed to radiation; Transparency refers to the surface of a material that has completely penetrated radiation.

13, Trim, modify the value, finish

The Resistor of carbon glia grid type (Resistor), when the thickness and width of the hardened resistor are fixed, can still be adjusted accurately by sand blasting or laser method and its resistance value can be controlled. And the overflow of excess carbon glue, can also be cleared with the same method, known as Trim. The term is also used in reference to the numerical refinement of resistors, capacitors, or coils in other manufacturing methods.

14, Trimming

In the thin film or sheet element (such as resistor or capacitor, etc.), the length, width or shape can be trimmed by laser beam or sand blasting method, and the required value is modified, called Trimming.

15. Tungsten

Tungsten, also known as Wolfram, has an element symbol of W, an atomic order of 74, an atomic weight of 183.85, and valence numbers of 2, 4, 5 and 6. The melting point is as high as 3410℃, which is the highest among metals. Tungsten is also a very hard metal with good electrical conductivity, so it can be used as a low voltage contact and incandescent filament.

16. Turnkey System

Refers to a process equipment or connection whose supplier has prepared the software and hardware details required for operation, and the user only needs to activate the key to work. Even some newly established factories can start production as soon as they open their doors. The whole factory can also adopt all-inclusive supply, the mainland industry known as a "key factory".

17. Ultimate Tensile Strength(UTS)

When the tensile strength sample is placed on the tensile test apparatus, the maximum tensile value presented until the breaking point is called UTS. This value is important for metal materials with structural strength requirements.

18, Unbalanced Transmission Line

differential Transmis sion Line When there are two parallel signal lines in each Microstripe or Stripline transmission line, the differential transmis sion line is called "balanced transmission line", or differential transmis sion line. If only 1 signal line is called "unbalanced transmission line".

19. Urea

A white crystalline or powdered odorless chemical with the formula CO(NH2)2 that occurs naturally in urine, urea was the first synthetic polymer used as fertilizer and feed. The thermosetting resin synthesized with formaldehyde can be used as electrical insulating material.

20. Urethane thane

The thermosetting resin Poly-Urethane(PU for short), which is formed by the polymerization of the monomer, is a common insulating material and can also be foamed as a material for encapsulation and packaging. Because of its wear resistance, moisture resistance, chemical resistance are very good, and the surface is very smooth, it is often used as an insulating material in the electronic field.

21. Vacuum Evaporation (or Deposition) method

In a sealed vacuum system, the metal to be gilded is heated so that it evaporates, and so that the uniform settlement on the surface of the object to be treated, such metal surface treatment method is called "vacuum evaporation method". Aluminum is the most widely used form of steam gilding. A very thin gold coating is often applied to the back of a semiconductor wafer to facilitate a variety of joint operations. CD or disc, also often steamed with bright gold layer and silver aluminum layer, thickness is very thin.

22, Van Der Waals Force

The weak force of positive and negative electric attraction between polar molecules is called "van der Waals force". The electrostatic attraction between ammonia molecules is an example, as is the hydrogen bond in water molecules.

23. Vapor Degreasing Method

It is the use of organic solvent heated evaporation rise, and condensation to the product to be cleaned, after dissolving the dirt and then drop back into the heating tank. This method can make a lot of dead space to be washed, through continuous fresh steam wash, its results are cleaner and more effective than other immersion methods. Trichloroethane is the most common solvent used.

24. Vickers Hardness

Is a unit of the "microhardness" of electrodeposited coatings. The Indentation is presented as a three-dimensional diamond shaped by an inverted pyramid, with the intersection Angle of the diagonal triangular prism of the diamond being 136°, the length of the diagonal base line being d, and the depth of the indentation bottom point being p. And d is 7 times p. The hardness can be abbreviated to MHV (Hardness Vickers) and the formula is MHV = (1854.4×P)/D2. Note that there is no conversion of this Vickers Microhardness number to the other Knoop microhardness number.

25, Vulcanization , crosslinking

When an elastic material (Elastomer) undergoes a sulphide reaction, or other type of cross-linking bridging reaction, resulting in a change in its physical properties, it is called vulcanization or cross-linking.

26. Washer

It is a small flat ring with a hole in the middle, which can be processed by metal or plastic. To match screw and nut locking.

27. Wave Guide

An external device used to transmit and receive energy from electromagnetic waves, such as microwaves, a metal tube that functions like an ear. The forms are Electroforming in copper or nickel, the inner walls of which are plated with silver and transmitted by microwave reflection. Wave Guide is an important product of the electroforming industry, which only emerged during the Second World War. The continental term is "waveguide". In a kitchen microwave oven, there is another type of waveguide device that emits microwaves.