【正文】 內(nèi)電場的，方向從 N區(qū)指向 P區(qū)，當(dāng)受到光照時，將產(chǎn)生電子和空穴，在內(nèi)電場作用下，電子被吸 引到 N區(qū)，空穴被吸引到 P區(qū)，如果用導(dǎo)線或外接電阻連結(jié) PN結(jié)，將形成通過外電路的電流。為了使電子從價帶激發(fā)到導(dǎo)帶，入射光子的能量應(yīng)大雨材料的禁帶寬度，即入射光玻波長應(yīng)小于入。 光敏二極管 我們知道，在半導(dǎo)體中只有導(dǎo)帶中的電子和價帶中的空穴才能才 能起導(dǎo)電作用。輸出電阻和電流調(diào)整率。測試電路如圖。再經(jīng)濾波電路濾除較大的紋波成分，輸出紋波較小的直流電壓 U1。 交流電壓變換部分：將交流電網(wǎng)提供的電流電壓變換到電子電路所需要的交流電壓，同時還可起到直流電源與電網(wǎng)的隔離作用。 淮安信息職業(yè)技術(shù)學(xué)院 2 單束主動式紅外計數(shù)器 優(yōu)點(diǎn)：價格相對較低 ,結(jié)構(gòu)簡單 . 缺點(diǎn)：不能辨別行進(jìn)方向，車輛是進(jìn)還是出，只適用于單一通道。當(dāng)有車輛擋住紅外光 時，接收管沒有接收到紅外信號，放大器將輸出低電平，同時計數(shù)器計數(shù)這個低電平脈沖，并經(jīng)譯碼驅(qū)動電路使數(shù)碼管顯示相應(yīng)數(shù)值。 關(guān)鍵字： 光電耦合器、觸發(fā)器、可逆計數(shù)器、脈沖 Abstract The subject of counter intelligence carpark, the article focused on the use of the parking area, analysis of its work processes and principles, and as the basis for discussion of its use. The whole design from the following ponents: power supply, Photometric, to identify the direction of interlocking circuit (even rising edge of D flipflop), reversible Abstract II counter, preset number of circuits, decoding circuitry, show circuit. The main principle is to discuss the vehicles entering or leaving, after all Photometric the process, from Photometric output level of potential changes to the rising edge of the doubleD trigger signal, according to the traffic passing vehicles Out, the output will be sent corresponding to the pulse signal to the counter, will be irreversible counter to the pulse of the receiving signals or by counting and counting, and the decoder, from forepart digital display of the existing car parks The number of parking spaces. At the same time the use of circuit switching codes to be reversible counter to the preset number, and in this counting on the basis of addition and subtraction. Key Words: photometric trigger reversible counter pulse 目錄 III 目錄 摘 要 .................................................................................................................................... I 第 1 章 緒論 ...........................................................................................................................1 常用計數(shù)器件 .............................................................................................................1 電路結(jié)構(gòu) ....................................................................................................................2 第 2 章 直流穩(wěn)壓電源 .............................................................................................................3 直流穩(wěn)壓電源的組成 ...................................................................................................3 原理與分析 .................................................................................................................3 穩(wěn)壓電流的性能指標(biāo)及測試方法 .................................................................................4 基本驅(qū)動方式 .............................................................................................................6 光敏二極管 .................................................................................................................6 圖 32 光電二極管外形圖 .................