【正文】 uitable for operation, and orientation to conspicuous. As for welding technology, this is the usual fundamentals. Welding process is good or bad, directly related to the design of finished product quality, it must be strictly required. In order to ensure products by vibration or impact was not fall off, bee loose, request solder should have good mechanical strength, In order to ensure good conductivity, request solder without welding, and welding deficiency is dependable, In order to ensure that the shape of solder joint surface is smooth, clean, no burr, the requirement with good solder rosin and soldering pen. In the welding process must control elements of welding time, avoid by heating time is too long and burnedout ponents. And welding connection do not have too much solder, avoid to cause a shortcircuit. The ponent ZhuangHan order is resistor, capacitor, diode, audion, integrated circuit, highpower tube, other ponents is first small after big. In order to debug, in the installation process the whole circuit I press unit circuit posed, one step one step of welding, general speaking first first welding power circuit of and ensuring it39。t shut automatically. Also caused much waste. In daylighting point where can be installed outside the classroom when indoor daylighting points, a strength the difference value is narrowed to a certain range, we can think fluorescent lamp role can neglect, fluorescent lamp will automatically closed. Another option, if it is raining outside the classroom, classroom inside the sun lights on and at the window, make a lightning outside is very bright, fluorescent lamp had closed down, which can cause trouble. So to avoid this problem. Methods is in circuits installed counters, makes the brightness difference in maintaining a certain time just can make fluorescent lamp pulsory closed. To sum up, we can use light activated triode design a circuit, making the fluorescent lamp couldn39。t reliable direct drive dc relay, reason need to add level 1 transistor amplifier, so the driver output portion posed by the transistor and relays. This circuit relay models 4098, dc resistance to 300 Ω, drive current for 200 ma, reason transistor collector current should be more than 300 ma, set transistor current amplification coefficient for 50, the beta transistor turnon the base current for 300/50 = 6 (ma). Can be calculated resistance R10 = (6V V) / 6mA hundredth 9K Ω, so this circuit Ω R10 take 10 K, triode can be used for 9013, maximum output current 500 milliampere. 5 and photosensitive sensor This circuit photosensitive sensor adopts light activated triode 3DU31, it is one of the most mon photodetector, its sensitive wavelengths in the visible wavelength near infrared wavelength and ultraviolet ray, including wavelength. Light activated triode and ordinary triode similar, also have current amplification e ffect, but it is not just the collector current by passive circuit and current control, but also by ray radiation control. Usually base not derivation, but some light activated triode base have derivations, used for temperature pensation and additional control functions. When having photosensitive properties of PN junction by irradiation, formation, thus resulting in the light of photocurrent born by base into emitter current collector loop, in order to get an enlarged equivalent to beta times the signal current. Different material made of light activated triode have different spectral characteristics and pared with photosensitive diode, has the very big photocurrent amplification, namely high sensitivity. Through to the semiconductor diode and triode learning, I understand the transistor the basic structure and working principle of semiconductor, transistor, is one of the basic ponents, with current amplification effect, is the core of electronic circuit ponents. Transistor is in a semiconductor substrate production two are located very close of PN junction, the two PN junction is divided into three parts, block semiconductor middle part is basebed, two side part is the launch region and integrating electricity area, arrangement have PNP and two NPN transistors, as shown in figure drawn from three areas corresponding electrode, respectively base b emitter e and collector c. Launch region and basebed between PN junction that launch knot, bines electronic zone and basebed between PN junction called the collector. Basebed is very thin, and launch region thicker, impurity, PNP transistor concentration large type emission region fire is the direction of movement, the cavity with current direction, reason emitter to the arrow, NPN transistor launch region firing type is free electrons, which the movement direction and current in opposite directions, so emitter arrow outward. Emitter arrow outward. Emitter arrow in also PN junction in forward voltage under the conduction direction. Silicon transistor and germnium transistor have PNP type and NPN type two kinds. Although key learning transistor amplifying function of transistors, but I more interested in the switch function. Semiconductor like a switch, can pass conduction and the due to control circuit. Semiconductor by adding part of trace element will make its characteristic earthshaking changes. Photo transistor is a kind of important derivatives. Human body is the most important visual sense, therefore, I think through light to control circuit is really too subtle, and photosensitive diodes triode just can finish this task. Because light activated triode due to still have amplification, therefore application than diode more extensive. Light activated triode is used for measuring brightness, often with light emitting diode is used together as a signal receiving devices. Use examples below introduce various functions. (1) measurement brigh