It can be seen as the reliability test for TECs to make continuous thermal cycling to TECs in a wide temperature rang. Especially temperature of TECs in this process rises to very high. Compared with most applications, this process will cause higher failure rate. Most of failures are rooted in unmatched thermal expansion coefficients of thermal materials and other components. This is inevitable. It performs as initial failure, but sometimes, performance degeneration will be observed before failure.(more)

High reliability and long life time can be achieved when the thermal cycling times is few, the temperature change range is narrow, upper temperature limit is low, as well as that temperature change is slow. On the contrary, in a wide temperature range, high changing speed, many times cycling, it will shorten the life time of TECs largely. It's noteworthy that the absolute life time of TECs depends largely on the total cycling times, not the total time for the cycling.(more)

Thermoelectric cooler (TEC) plays an important role in its application products. According to the characteristics, weakness and application range, the following problems should be determined when selecting TEC.(more)

Continued from the last article. 5. Determining TEC series Selecting TEC series must meet the actual temperature difference requirements, that is, the nominal temperature difference shall be higher than the actual temperature difference, so that it can meet the requirements. However, the series is not too much because TEC price has great improvement with the increase of series.(more)

Thermoelectric cooler (TEC) is also called semiconductor cooler, which is using an artificial cooling technology based on Peltier effect. At present, the focus of domestic and foreign researches is on the characteristic optimization of TEC itself thermoelectric materials, but there are few researches on the combined influence of TEC performance. The main integrated influence factors of TEC internal structure include geometry size of the thermoelectric arm, contact effect and so on.(more)

Since the TEC module structure is constructed in a solid state, it's common to regard it as having high reliability. In most applications, TECs can provide long term fault-free services. At present, in many practical applications, the service life of TECs exceeds 20 years, longer than other relative devices. However, failure rate is closely related to the application environment, so it's difficult to achieve detailed reliability of TEC modules. For some stable cooling applications, a stable and continuous power supply is connected to TEC modules, in which condition the reliability of TECs will be very high. MTBFs are less than 2000,000 hours, which is seen as industrial standard. On the other hand, in the application of thermal cycling, MTBFs will be largely shortened, especially when the TEC increases to a high temperature in thermal cycling process.(more)

Thermistor is a kind of sensitive elements, which can be divided in two types, PTC thermistor and NTC thermistor, according to different temperature coefficients. The typical characteristics of thermistor are that at different temperatures, it can show different resistance values. With increase of temperature, the resistance of PTC can increase and the resistance of NTC can decline. PTC and NTC both belong to semiconductor devices.(more)

A glass encapsulated thermistor mainly plays a role of temperature compensation. There are some kinds of packaging materials, such as epoxy resin, SMD, glass and so on. The glass encapsulative has high temperature resistance and moisture resistance. However, comparing with some other packaging forms, its responding speed is a little slow, around ten senconds.(more)

Based on the Piltier effect, thermoelectric cooling is an energy conversion process, using electric energy as power, that is: when the direct current is through two different conductive materials, nodes will have endothermic phenomenon (when the current is in the opposite direction, exothermic phenomenon will be generated). As the Peltier effect of semiconductor materials is very obvious, the thermoelectric modules are mostly made up of semiconductor materials at home and aboard.(more)

Laser is a kind of light source components. In actually, drive circuit refers to modulation circuit of light source device, which plays a role of converting digital signal to optical pulse signal and then sending to fibers. This part is the core of optical transmitter, which decides many important technical parameters.(more)