cufflinks

Software Testing Technology is constantly updated and improved, new tools, new processes, new test methods are constantly updated, need to know and learn a lot of testing knowledge. Therefore, a programmer with programming experience is not necessarily a good test engineer. Software testing included both technical and management aspects fully grasp the content of these two aspects, you need a lot of testing of practical experience and continuous learning spirit. Myth Four: Software testing is a thing of the testers and programmers. Development and testing is a complementary process that requires the software testers, programmers and systems analysts maintain close ties, the need for more communication and coordination in order to improve test efficiency. The ordinary or advanced design will determine whether the quality and structure of laser pointers are good enough or not. Red Laser
The external string into the interference signal will also produce instant high current, so that long-term work will also affect the service life of semiconductor lasers. On this basis, in the design of the introduction of slow-start circuit, connected diode and capacitor in the reference input and the capacitance of which around 10 ~ 470μF, the best value in 22 to 47μF. In this way, the drive circuit from the interference of the power supply voltage has the effect of slow start, so that the laser will not be over-current shock, every time you turn on the power to extend the life of the laser. APC circuit controls the process is as follows: For some reason, the LD output light power is reduced, coupled to the photodiode current is reduced the same proportion. It is the short and small type laser pointers. Zumba DVD
V1 decreases, so that the normal state of balance is broken, making the op amp output voltage V3 will be increased, therefore, the transistor Q1 base current increases, the collector current increases, while the The collector current is the flow into the current of the LD. Therefore, the current flowing into the laser increases, the output optical power is increased accordingly, so that the optical output power remains the same; the contrary, is no different. According to the parameters of the laser performance of the sensor, select the appropriate resistance and capacitance to match, adjust the potentiometer can be a different optical power output values. Figure 5 is the experimental curve at room temperature (25 ° C), can be seen from the figure: the threshold current of the LD light source of the optical fiber sensor about 8 mA, stable between 10 ~ 30mA. laser pointers has the high performance so that the laser pointer is strong and firm enough.
Output power with drive current is greater than the threshold current was a good linear relationship. Normal working hours to output -0.1, -1, -2, -5, -10 dB, adjustable and stable optical power value. Configuration parameters in the circuit, the current into the LD does not exceed its limit. The results show: the design of the circuit is correct and feasible, based on the back of the monitor automatically the optical power feedback to ensure the normal work of the optical fiber sensor in the case of constant power. Designed driver circuit, through the slow start and the power of automatic control circuit to solve the problem of the laser output power instability in use, its stability better than 0.5%, to a good steady flow effect. The fiber optic sensors in this article is applied to the liquid nitrogen cryogenic environment. So that the quality and performance of laser pointers can be increased to a higher level.