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使用3個bits控制8個類比輸入分歧器。下圖左方是ic腳分配圖，右邊經由s0 s1 s2三個bit決定輸出z的對象（y0~y7）是誰。使用一顆4051的情況下可以用三個數位輸出當做切換頻道的選擇；如下表所示。

 兩顆4051以上組合達到更多類比輸入。

以下左方的電路組合，使用九顆4051與六個數位輸出來切換頻道(s0~s5)，最左邊的憑到輸出可以共用。右方使用兩顆4051做矩陣式的開關偵測，但是必須在上方的4051元輸出z pin接上vcc電源與電阻經過中間64個開關線路接地。

/* * codeexample for useing a 4051 * analog multiplexer / demultiplexer * by david c. and tomek n.* for k3 / malm� h�gskola * * edited by Ross R. */ int r0 = 0; //value of select pin at the 4051 (s0) int r1 = 0; //value of select pin at the 4051 (s1) int r2 = 0; //value of select pin at the 4051 (s2) int count = 0; //which y pin we are selecting void setup(){ pinMode(2, OUTPUT); // s0 pinMode(3, OUTPUT); // s1 pinMode(4, OUTPUT); // s2 } void loop () { for (count=0; count<=7; count++) { // select the bit r0 = bitRead(count,0); // use this with arduino 0013 (and newer versions) r1 = bitRead(count,1); // use this with arduino 0013 (and newer versions) r2 = bitRead(count,2); // use this with arduino 0013 (and newer versions) //r0 = count & 0x01; // old version of setting the bits //r1 = (count>>1) & 0x01; // old version of setting the bits //r2 = (count>>2) & 0x01; // old version of setting the bits digitalWrite(2, r0); digitalWrite(3, r1); digitalWrite(4, r2); //Either read or write the multiplexed pin here } }