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TTL电路是常用的集成电路,这里介绍一种简易检测方法。 1.好坏检测:TTL芯片除腿脚数目有差别,其电源脚(V_(cc))与地脚(GND)封装位置都是一样的,对于有2N脚的TTL芯片,第2N脚为V_(cc),第N脚是地,如74LS74为双7脚TTL芯片,则第⑦脚为地,第⒁脚为V_(cc),可用指针式万用表RXlK档测其引脚电阻值(不能用数字万用表,因其内阻较大,影响结果)。则得读数有以下四种情况:(1)短路(正反向电阻均为零);(2)断路(正反向阻值为无穷大);(3)正反向阻值相似,
TTL circuit is a commonly used integrated circuit, here is a simple detection method. 1. good or bad detection: TTL chip leg number difference, the power pin (V_ (cc)) and the ground pin (GND) package location are the same, for the 2N pin TTL chip, the first 2N pin V_ ( cc). The Nth pin is ground. If the 74LS74 is a dual 7-pin TTL chip, the ⑦ pin is ground, the ⒁th pin is V_ (cc), and the pin resistance of the multimeter RX1K can be measured Multimeter, because of its larger resistance, the impact of the results). You have to read the following four situations: (1) short circuit (positive and negative resistance are zero); (2) open circuit (positive and negative resistance is infinite); (3) the positive and negative resistance is similar,