Eight core SYV - 75-5 coaxial cable of the radio frequency cable, home video line, etc., are SYV solid core polyethylene insulated PVC sheathed coaxial cable, 75 of which means the resistance of the conductor is 75 ohms, 5 large diameter refers to the insulation of the cable is 5 mm (4.8 + / - 0.2 mm), 5 instead of 7, 7 cannot replace with 5, because insulation in large and small, not big to small generation.
特种电缆就是有特殊用途、可以在特定场合使用的电缆，比如可以耐高温，耐酸碱，防白蚁，以及在轮船飞机核电站等场合使用的电线电缆。
就分类来说，它与电力、控制、计算机电缆等类别不属于同一种分类方法，也就是上列电缆中也包含有特种电缆在内。
一般特种电缆都需要制定企业内控标准。
航空航天、机车车辆、能源、钢铁、有色金属冶炼、石油开采、电机、建设等领域需用耐高温电线电缆。
长期连续工作温度135度、180度、250度及
有强电与弱电之分，这里介绍一种强电用低感电缆。
此电缆带有热耗散装置，用于各类接触焊机、电弧焊机与气动焊钳间相连接的新型水冷式低感电缆，具有结构简单合理、冷却水流通量大、不会形成堵塞阻断和限流现象、散热效果好、使用寿命长等特点。
RVVSP shielded twisted-pair cable, used in the field lines, electrical instrumentation, telecommunications, broadcasting, anti-theft alarm system, building intercom system, video monitoring system, electronic equipment and automation devices such as shielding line. (transmission RS485 signals /) our factory new micro sales letter, micro signal: 15075619608 QQ is not convenient to micro letter contact! Conditions of use 1: using temperature (℃) : - 40 ~ 60 + 2: relative humidity: 98% at 40 ℃ 3: install the laying temperature is not low, such as: 15 ℃ 4: allowed minimum bending radius: indoor is not less than five times, 10 times outdoor structure 1:2: tinned copper wire line core PVC insulated/twisted-pair cable 3: film around the package/tin copper wire mesh grid block 4 PVC sheathed rated voltage: 300 v / 300 v, 300 v / 300 v with a standard: GB/T5023-1997 RVVP cable series: Can achieve 2 core to 24 core, line diameter has: 0.5, 0.75, 1.0, 1.5, 2.0, 2.5, 4.0, etc. (zr-rvvsp flame retardant),(nh-rvvsp fire resistance),(wdz-rvvsp low smoke halogen free) special model can be produced as required
The marking contents of armored communication cables include: wire diameter, number of wire pairs, cable model, length, manufacturer name and year of manufacture.
二极管最基本的工作状态是导通和截止两种，利用这一特性可以构成限幅电路。
所谓限幅电路就是限制电路中某一点的信号幅度大小，让信号幅度大到一定程度时，不让信号的幅度再增大，当信号的幅度没有达到限制的幅度时，限幅电路不工作。
利用二极管来完成这一功能的电路称为二极管限幅电路。
所示是二极管限幅电路。
在电路中，A1是集成电路（一种常用元器件），VT1和VT2是三极管（一种常用元器件），R1和R2是电阻器，VD1～VD6是二极管。
25-50V、电流在“梅花芯“轮心“辐条