【文章內(nèi)容簡(jiǎn)介】 own, as shown in figure 7, transmitter aimed at the target launch beam, the launch of the beam from semiconductor illuminant, general light emitting diode (LED), laser diode and infrared emission diode. Beam uninterrupted launch, or change the pulse width. Receivers have photoelectric diode, photoelectric triode, posed sibased ones. In front of the receiver, equipped with optical ponents such as lens and aperture, etc. In its back is detection circuit, it can filter out effective signal and the application of the signal. In addition, the structural ponents in photoelectric switch and launch plate and optical fiber, triangle reflex plate is solid structure launch device. It consists of small triangle cone of reflective materials, can make a beam accurately reflected back from plate, with practical significance. It can be in with the scope of optical axis 0 to 25, make beams change launch Angle from a root almost after launch line, passes reflection or from the rotating basic returns. 圖7Photoelectric sensor is a kind of depend on is analyte and optoelectronics and light source, to achieve the relationship between the measured purpose, so the light source photoelectric sensor plays a very important role, photoelectric sensor power if a constant source, power is very important for design, the stability of the stability of power directly affect the accuracy of measurement, monly used illuminant have the following kinds: 1, leds is a change electric energy into light energy semiconductor devices. It has small volume, low power consumption, long life, fast response, the advantages of high mechanical strength, and can match and integrated circuits. Therefore, widely used in puter, instruments and automatic control equipment. 2, silk light bulb that is one of the most monly used illuminant, it has rich infrared light. If chosen optoelectronics, constitutes of infrared sensor sensitive colour filter can be added to the visible tungsten lamps, but only filter with its infrared does illuminant, such, which can effectively prevent other light interference. 3, pared with ordinary light laser laser with energy concentration, directional good, frequency pure, coherence as well as good, is very ideal light sources. The light source, optical path and photoelectric device position photoelectric sensor used in photoelectric detection, still must be equipped with appropriate measurement circuit. The photoelectric effect to the measurement circuit of photoelectric element of widerange caused changes needed to convert the voltage or current. Different photoelectric element, the measurement circuit required is not identical also. Several semiconductor introduces below optoelectronic devices monly used measurement circuit. Semiconductor photoconductive resistance can through large current, be in so usually, need not equipped with amplifier. In the output power of demand is bigger, can use figure 8 shows circuit. Figure 9 (a) with temperature pensation given the photosensitive diode bridge type measuring circuit. When the incident light intensity slow change, the reverse resistance photosensitive diode is the slow change, the change of the temperature will cause the bridge output voltage, must pensate. Drift Picture a photosensitive diode as the test ponents, another into Windows, in neighboring bridge, the change of the temperature in the arms of the influence of two photosensitive diode, therefore, can eliminate the same output with temperature bridge road drift. Light activated triode incident light in work under low illumination, or hope to get bigger output power, also can match with amplifying circuit, as shown in figure 9 shows. Because even in the glare photosensitive batteries, maximum output voltage also only V, still cannot make the next level 1 transistor have larger current output, so must add positive bias, as shown in figure 9 (a) below. In order to reduce the transistor circuit impedance variations, base sibased ones to reduce as much as possible without light, when the reverse bias inherit in parallel a resistor sibased ones at both ends. Or like figure 9 (b) as shown by the positive ge diode produces pressure drop and test the voltage produced when exposed to light, make silicon tube e stack, b the voltage between actuators than V, and conduction work. This kind of circumstance also can use silicon light batteries, as shown in figure 10 (c) below. Semiconductor photoelectric element of photoelectric circuit can also use integrated operational amplifier. Silicon photosensitive diode can be obtained by integrating opamp larger output amplitude, as shown in figure 11 (a) below. When light is produced, the optical output voltage in order to guarantee photosensitive diode is reverse biased, in its positive to add a load voltage. Figure 11. (b) give the photocell transform circuit, because the photoelectric sibased ones shortcircuit current and illumination of a linear relationship between, so will it up in the opamp is, inversephase input, using these two potential difference between the characteristics of close to zero, can get better effect. In the picture shows conditions, the output voltage The photoelectric element by flux the role of different made from the principle of optical measurement and control system is varied, press the photoelectric element (optical measurement and control system) output nature, namely, can be divided into second analog photoelectric sensor and pulse (switch) photoelectric sensor. Analog photoelectric sensors will be converted into continuous variation of the measure, it is measured optical with a single value relations between analog photoelectric sensor. According to be measured (objects) method detection of target can be divided into transmission (absorption) type, diffuse type, shading type (beam resistance gears) three categories. Socalled transmission style means the object to be tested in optical path in con