Wintop Bluetooth Earphones: Fashion and Cosy Design

Wintop Bluetooth Earphones

In-ear Sports&Gym Bluetooth Stereo earphone with Aviation aluminium design

1. Bluetooth V4.1+EDR with faster transmission and lower power consumption;

2. Ergonomics design,suitable for long using; with highly flexible wing for more comfort and fastness                                             

3. 12mm speaker driver unit, perfect audio output;

4. Built-in HD microphone and noise elimination,High quality talk performance;

5. Micro USB charging port,160mAh rechargeable battery;

6. Up to 8-9 hours play time and 320 hours standby time;

7. Connect with two Bluetooth devices at the same time;

8. Battery status displays on IOS.      

Knowledge: What Is Thermistors?

Thermistors belong to sensitive components, divided into positive temperature coefficient thermistor (PTC) and negative temperature coefficient thermistor (NTC) according to the temperature coefficient. The typical characteristic of thermistors are sensitive to temperature and output different resistance values at different temperatures. Positive temperature coefficient thermistors (PTC) show the larger resistance at higher temperatures, negative temperature coefficient thermistor (NTC) show smaller resistance at higher temperatures, all of which are semiconductor devices.

Features of Thermistors
1. High sensitive, TCR is 10-100 times larger than metal and it can test 6-10℃ temperature shift.
2. Work temperature range is wide, normal temperature resistors are applied to -55℃～315℃, high temperature resistors are applied to 315℃(at present it can be used at temperature of 2000℃), the low temperature resistors are applied to -273℃～-55℃.
3. Small dimension, it can measure temperatures of the voids, cavities and blood vessels in biological body that other thermometers cannot measure.
4. Easy to use, resistance can be 0.1～100kΩ.
5. Easy to process complicate shapes and mass produce.
6. High stability and strong overload capacity.

Materials of Thermistors
Materials of thermistors contain semiconductor, metal and alloy.

Semiconductor material: they have strong TCR and high resistance rate, and the convertor made of this material is very sensitive. It can be used for thermistor thermometer, thermistor switch, etc.

Metal material: high stability and high precision for platinum convertor. Platinum resistor thermometer and copper resistor thermometer, etc.

Alloy material: it has higher resistance rate and resistance is sensitive to temperature, very good to make thermal sensitive convertor. They are widely used for temperature monitor, such as fields of environment monitor, food long-term storage, biological engineering and sophisticated military engineering.

Knowledge: What Is Wirewound Resistors?

Wirewound resistors are made of copper, manganese or nickel-chromium alloy wire wound around the ceramic skeleton of a resistor, there will be a protective paint or glass glaze on the surface.

The advantages of wirewound resistors are low noise, no current noise and non-linearity. Small temperature coefficient, good stability, accuracy can reach 0.5% -0.05%, wirewound resistors can be used for high frequency. The shortness is poor high-frequency characteristics.

Wirewound resistors are resistors wire wrapped around the insulation skeleton and then insulated package processed. The resistance wire generally uses a certain resistivity of nickel-chromium, manganese and other alloys to make, insulation skeleton generally use ceramic, plastic, coated metal frame insulation. This kind of resistors has a small temperature coefficient, high accuracy. Among the wirewound resistors, there is a high power wirewound resistor made of ceramic, coated with a glaze or other heat-resistant and heat-dissipating insulating material on the outer surface of the resistor.

There is also an adjustable wire wound resistor in the wirewound resistors, which is wound on the outside with removable snap rings as contacting leads, with a long and narrow window above the glaze, revealing wire wound channel, snap ring move by contacting contact to adjust the resistance, it is an adjustable resistor. There are two common types of wirewound resistors: glazed wirewound resistors and enameled wirewound resistors.

Wirewound resistors are used in mobile phone chargers. Wirewound resistor value is accurate, in theory, unless it is to do the charger output voltage reference, the general charger does not use wirewound resistors, mobile phone charger circuit is SMPS switching power supply circuit, high-voltage side signal generating circuit has higher requirement, it is impossible to use wirewound resistors, otherwise it will lead to self-oscillation to impact oscillation frequency, so that the output fluctuations, only the low-voltage end uses sampling reference circuit that may use wirewound resistors ...... A cell phone charger circuit is not high precision electrical, do not need to calculate the capacitance and inductance of the PCB board into it, and the switching power supply itself has very large fluctuations, a wirewound resistor filtering effect is minimal.

High Voltage Resistors

The impediment to the current of the conductor is called the resistance of the conductor. High-voltage resistors are the most commonly used element in all electronic circuits. The main function is to hinder the current flow, used in current limiting, shunt, drop voltage, partial pressure, load and capacitor for the filter and impedance matching, etc. Digital circuits have pull-up resistors and pull-down resistors.

Resistors are the most used component in all electronic circuits. The main physical feature of a resistor is transferring the electrical energy to thermal energy. It can be named a dissipative component that generates internal energy when current passes through it. Resistors in the circuit usually are the role of partial pressure shunt, for the signals, both AC and DC signals can pass through the resistors.

Resistor has a certain resistance, which represents the size of the resistor's blocking force on the current flow. The unit of resistance is ohm, symbol "Ω". In the SI system, the unit of resistance is Ω, in addition to mΩ, KΩ, MΩ. Exchange formula: 1MΩ=1000KΩ=1000000Ω=1000000000mΩ.

High voltage resistors are suitable for use in high voltage, high voltage shock, high voltage and high frequency environments. Here are classification for high voltage resistors below:

1. Tubular ceramic non-inductor high voltage resistors are 100% ceramic body resistors, pure non-inductor, high voltage resistance, the maximum impact voltage is up to 75KV, can withstand greater current, higher peak energy in short times; no failure phenomenon like wire wound resistors and molded resistor.

2. High-voltage lead-free wafer resistors are sintered by using a mixture of metal oxides and ceramic materials at high temperatures. They can withstand the effect of instant high temperature and high pressure, mainly applied in cars and motorcycles ignition.

3. High-pressure metal-ceramic damping resistors have superior high-voltage high-current surge characteristics, and more stable than the wire wound resistors and film resistors. Suitable for high-voltage circuit design.

4. Oxide film high voltage high frequency resistors use tubular ends which are silver or gold electrode structure, mainly used for UHF circuit load.

5. Rod-shaped high voltage glass glaze film resistors are mainly used in AC or DC circuits, pulse circuit and high-voltage equipment.

6. Flake high voltage glass glaze film resistors are mainly used in AC and DC circuits, pulse circuits and high-voltage equipment.

Temperature Coefficient of Resistance and the Relationship between Resistance and Temperature

Yesterday I have a brief introduction of temperature coefficient of resistance (short for TCR), which  means when the temperature of the resistor changes 1 centigrade, the resistance value changes accordingly, and the unit is ppm/℃. There are negative temperature coefficient, positive temperature coefficient and critical temperature coefficient that resistance occurs at a particular temperature.

Resistors have parameters, what relationships are among them? A brief introduction of resistance and temperature will be given. Actually the conductor resistance has relationship to temperature. Temperature coefficient of resistance has positive temperature coefficient and negative temperature coefficient, which is related to resistor materials. The resistance of pure metal resistors rises with increasing temperature. When the temperature rises １℃, resistance will increase several parts per thousand. The resistance of carbon and insulator decreases with increasing temperature. The relationship between the semiconductor resistance and temperature is big, when the temperature slightly increases, resistance decreases dramatically. Some alloys such as konstantan alloy and manganese bronze resistance has little relationship with temperature changes.

Because of the temperature is an important factor for resistors, it is necessary to learn more about your application when choose a correct resistance. Microhm Electronics provides and manufacturers precision foil resistors. According to different requirements, Microhm provides different suitable resistors and services. 

Introduction of Thin Film Resistors

Thin film resistor is made by using a certain resistor materials deposited on the surface of the insulating materials with vacuum evaporate plating technology, generally this resistor uses insulation materials like ceramic wafer.

Thin film resistors has island structure, mesh structure, continuous structure. The materials are metal, metal alloy, etc.

In recent years, with rapid growth of electronic information technology, A/D, D/A change-over circuit and other linear and non-linear circuits are developing daily. High precision operational amplifier coring on thin film resistors website and A/D, D/A change-over circuits are essential. In order to improve precision and definition of ADC and DAC, the performance of thin film resistors should be improved as well.

DAC and ADC precision and definition are determined the resistor network of component interior. Resistor network performance analysis and production are the key technologies of simulating device development and production. High precision resistors have high resistance value, low TCR, high stability, no parasitic effects and low noise, etc, widely used in aviation, national defense, computer, communications equipment, electronic switches and other high-tech fields.

The formation of a thin film is essentially a gas-solid transformation, a process of crystal formation. It can be roughly divided into the following major steps: atoms or molecules impinge on the surface of a solid; they are absorbed by atoms on a solid surface or directly back into space; the adsorbed particles migrate or diffuse on the solid surface and move to the appropriate lattice sites on the surface and into the lattice. These processes and the interrelationships between them determine the film formation process and the properties of the film.

In general, the resistor film contains up to three types of phase components: the insulating phase, the semiconductor phase and the conductive phase. In modern resistor films, these phases are often finely distributed and some are even linearly distributed, because the coarsely dispersed structure makes the film poor performance.

According to the conductive phase or the semiconductor phase in the resistor film in the fine distribution, the film has such three structures: island structure, mesh structure and continuous structure. The island structure means that the conductive particles are finely dispersed in the island in the film, and thus each particle is surrounded by the insulating phase. Mesh structure is the conductive particles connected to each other into a conductive network, in the network hole is insulated phase. The continuous structure is that conductive particles closely packed into a continuous film, seldom containing the insulating phase.

Temperature Coefficient of Resistance (TCR)

Temperature coefficient of resistance (short for TCR) means when the temperature of the resistor changes 1 centigrade, the resistance value changes accordingly, and the unit is ppm/℃. There are negative temperature coefficient, positive temperature coefficient and critical temperature coefficient that resistance occurs at a particular temperature.

The temperature coefficient of resistance is a parameter that is closely related to the microstructure of a metal and has a theoretical maximum in the situation of no any defect. In other words, the magnitude of the temperature coefficient of resistance itself characterizes the performance of the metal process to a certain extent. In the development of new technology processes or on-line monitoring, we can use the temperature coefficient of resistance to evaluate the reliability of the metal for early monitoring and rapid assessment

Why is the temperature coefficient of resistance (TCR) important? Because the temperature changes on the resistance value of the resistance has a great influence. For example, a plane from tens of degrees environment to tens of degrees below zero environment, a few hours later from a few dozen degrees below zero to tens of degrees environment, the resistance will change with the temperature changes, either The resistance of a thin-film resistor or a thin-film resistor is affected by changes in ambient temperature.