当用一种材料校正仪器后(常用试块为钢)又去测量另一种材料时，将产生错误的结果。温度的影响。一般固体材料中的声速随其温度升高而降低，有试验数据表明，热态材料每增加100℃，声速下降1%。对于高温在役设备常常碰到这种情况。耦合剂的影响。耦合剂是用来排除和被测物体之间的空气，使超声波能有效地穿入工件达到检测目的。如果选择种类或使用方法不当，将造成误差或耦合标志闪烁，无法测量。实际使用中由于耦合剂使用过多，造成离开工件时，仪器示值为耦合剂层厚度值。
PV032R1K1T1NGLC
PV032R1K4T1NFHS
PV032R1K8S1NFWS
PV032R1K8T1NMMC
PV032R1K1T1WFDS
PV032R1K1AYNMTP
PV032R1K1T1NHCC
PV032R1K1T1WMM1
PV032R1K1AYNMRZ
PV032R1K8T1NFWS
PV032R1K1A4NFTZ
PV032R1K1T1VMMC
PV032R1K1T1NFPV
PV032R1K1A1VFDS
PV032L1E3C1NFWS
PV032R1K1T1NELB
PV032L1K1T1NFWS
PV032R1K1B1NFDS
PV032RAK1T1NF
PV032R1L1B1NFWS
PV032R1K1T1NFPG
PV032R1K1S1NFWS
PV032L1K1T1NMMC
PV032R1K1T1NMRZ
PV032R1K1T1VFDS
PV032R1K1T1N10045
PV032R1K1AYNMT1
PV032R1K8T1N001
PV032R1K1T1NHLC
PV032R1K4T1NFR1
PV032R9K1T1NMMC
PV032R1K1A4VFRZ
PV032R1K1T1NFRZ
PV032R1K1T1NMMK
PV032R1L1T1NMMC
PV032R1K4T1NMR1
PV032R1K1T1WMR1
PV032R9K1T1NMMCK
PV032R1K1T1NE1B
PV032R1K1T1NKLC
PV040R1K8T1NMMC
PV040L1K1T1NFWS
PV040R1K1T1NFRC
PV040R1K1T1NFFP
PV040R1K4T1NMR1
PV040R1K1T1NMR1
PV040R1K1T1NFR1
PV040R1K4T1NMMC
PV040R1K1T1NFDS
PV040R1K1T1NFF1
PV040R1K1T1NMRZ
PV040R1K1AYNMRZ
PV040R1K4T1NFHS
PV040R1K1T1WFDS
PV040R1K8T1VMMC
PV040R1K8T1N001
PV040R9K1T1NMMC
PV040R1K4T1NFR1
PV040R1K1T1N001
PV040R1K8T1NFWS
PV040R1K1T1VFDS
PV040R1K1A4NFRZ
PV040R1K1T1NMRC
PV040R1K1T1NMM1
PV040R1K1T1WMM1
PV040R1K1T1NMRK
PV040R1K1T1NHCC
PV040R1K1T1NMF1
PV040R1K1JHNMMC
PV040L1K1T1NMMC
PV040R1K1S1NFWS
PV040R1L1T1NMMC
PV040R1D8T1N001
PV040R1K1T1NMFC
为提高输入级的浪涌防护能力，在外围增加了压敏电阻和TVS管。但图中的电路、原目的是想实现两级防护，但可能适得其反。如果中MOV2的压敏电压和通流能力比MOV1低，在强干扰场合，MOV2可能无法承受浪涌冲击而提前损坏，导致整个系统瘫痪。同样的，电路，由于TVS响应速度比MOV快，往往是MOV未起作用，而TVS过早损坏。所以正确的接法一般是如图、所示，在两个MOV或是MOV和TVS之间接一个电感。
PV040R1K1T1NFWS
PV040R1K1T1WFR1
PV040R1K1T1NKLC
PV040R9K1T1NFWS
PV040R1K1T1NFFC
PV040R1K1T1NF
PV040R1K1T1N100
PV040R1K1T1WMR1
PV040R1K1T1NFRZ
PV040R1K1T1WMRC
PV040R1K1T1NMMK
PV040R1K1T1NMMC
PV040R1K1T1VMMC
PV040R1K1T1NFHS
PV040R1K1T1NGLC
PV040R1K1T1NHLC
PV040R1K1T1WMMC
PV040L1L1T1NFWS
PV040R1K1T1NMLC
PV040R1D1T1NGCC
PV040R1K1T1NELA
PV040R9K1T1NMMCK0188
PV046R1K1T1N001
PV046R1K1T1N100
PV046R1K1T1NFDS
PV046R1K1T1NFR1
PV046R1K1T1NFHS
PV046R1K1T1NMMC
PV046R1K1T1NMM1
PV046R1K1T1NMRC
PV046R1K1T1NFWS
PV046R1K1T1NFRC
PV046R1K1T1NFF1
PV046R1D1T1NFWS
PV046R1D3T1NFFC
PV046R1K1A1NF
PV046L1K1A1NFHS
PV046R1K1B1NFDS
PV046R1D1T1NHCC
PV046R1K1T1NFFC
PV046R1K1T1NMFC
PV046R1K1T1NMF1
PV046R9K1T1NMMC
PV046R1K1AYNMRC
PV046R1K1JHNMMC
PV046R9K1T1NFWS
PV046R1K4T1NMR1
PV046R1K4T1NFHS
PV046L1K1T1NFWS
PV046R1K1S1NFWS
PV046R1K1T1WFDS
PV046R1K1T1NMRZ
PV046R1K1T1EMMC
PV046R1K1T1WMMC
PV046R1K1T1NFFP
PV046R1K1A4NFRC
PV046R1K1T1VFDS
PV046R1K8T1NFWS
PV046R1K1T1WMM1
PV046L1K1T1NMMC
PV046R1K8T1VMMC
PV046R1K8T1NMMC
PV046R1K1T1NF
PV046R1K1AYNMRZ
PV046R1K1T1NHLC
PV046R1K1T1NMMK
PV046R1K1T1NKLC
PV046R1K1T1NMR1
PV046R1K1T1NFRZ
PV046R1K1T1WFR1
PV046R1K4T1NFR1
PV046R1K1T1WMR1
PV046R1K1T1NMRK
PV046R1K1T1WMRC
PV046R1K1T1NHCC
PV046R1K1T1VMMC
PV046R1K1T1NGLC
PV046R1L1T1NMMC
PV046R1K8T1N001
PV046R1K4T1NMMC
PV046R1K1T1NMMCX5934
PV063R1K1T1NMF1
PV063R1K1T1NMMC
PV063R1K1T1NMMK
PV063R9L1TNMPCK0
PV063R1K1A1VFPR
PV063R1K1C1NFWS
PV063R2K1T1N001
PV063R9L1T1NFWS
PV063R1K1A1NFHS
PV063R1K1T1NFFP
PV063R1K1T1NFPR
PV063R1K1T1NGLC
PV063R1K1T1N001
PV063R1K1T1N100
PV063R1K1T1NFDS
四线法：这是在三线法基础上的改进法。这种方法可以消除由于辅助地极接地电阻、测试引线及接触电阻引起的误差。仪器选择：目前市场支持此种方法的仪器比较多，其中以共立4105A-H接地电阻测试仪为代表。钳夹法：钳夹法分为单钳法和双钳法1双钳法:利用在变化磁场中的导体会产生感应电压的原理，用一个钳子通以变化的电流,从而产生交变的磁场,该磁场使得其内的导体产生一定的感应电压，用另一个钳子测量由此电压产生的感应电流,*用欧姆定律计算出环路电路值。
