膜电位器简化位置感应

剃刀薄，扁平膜电位器展开设计师的传感曲目。

Membrane potentiometers can solve many of the problems that conventional mechanical potentiometers cannot handle, especially those involving limited installation space, weight restrictions, and accuracy.

常规的机械电位器是电控和位置感测的旧主主。然而，与较新类型的装置，膜电位计相比，这些传统电位器可以重沉重，笨重和昂贵。

在一些仅测量的0.5mm厚的情况下，超扁平膜电位器在电气参数方面与传统电位计相当，但可用于安装空间有限的应用和成本较低。

Because most producers of membrane potentiometers offer customized products with only small tooling efforts, costs are very competitive, even for small prototype quantities. Three additional advantages are found in the basic construction of the membrane potentiometer; its ability to be fully sealed, the possibility of a hollow shaft design, and numerous wiper options, including operation by hand.

Design characteristics
通常，膜电位器是分压器。它被构造为开路电路，当刮水器通过向膜表面施加压力连接顶部和底部电路时，仅产生输出。顶部和底部电路之间的间距主要由密封剂粘合剂构成，密封抗外部环境因素，例如水分或灰尘。

大多数膜电位器可以密封到IP65（NEMA4x）等级及更远的额定值。常规电位器需要刮水器的难以组装，特别是在“空心轴”组件中。标准旋转电位器中间的孔难以生产，也很难从环境元素中密封。里面的刮水器必须是“游泳”，这使得难以密封并实现良好的线性度。通过膜电位器，空心轴设计更简单，更可靠，更具成本效益。

刮水器覆盖膜电位器上的约10至50％的主动宽度。典型的刮水器材料可以是钢，黄铜或各种硬塑料。

可以作为膜电位计的雨刷simple as a small plastic knob sliding across the surface, requiring no external electrical contact. Most membrane potentiometers can also be operated by sliding a finger over the surface or even with a contactless magnetic design.

The spacing adhesive requires a minimum width of 2 to 3mm on all sides of the membrane potentiometer. The ideal width of the resistive active area should be between 3 and 6mm, but can also be extended to 10 or 12mm. Linear elements can reach up to 760mm in active length, while rotary elements with a central hole can measure from 20 to 450mm in diameter.

生命周期和工作温度对应于机械电位器的寿命。然而，根据设计，即使是高达1亿的操作也是可能的。工作温度范围为40°C至85°C（104°F至185°F），有一些型号可实现125°C（257°F）的最高温度。膜电位器的设计如果以分压器模式操作，则不必要地使温度补偿不必要。电磁干扰也不会影响系统。

安装过程和刮水器设计
膜电位仪的平面设计意味着它们可以接近其测量的设备的运动区域，而无需大量安装空间。它们通过除去保护纸并将其施加到表面上粘附到基板上，其他选项包括卡扣安装或螺钉的使用。

With small quantities, off-the- shelf wipers might be the easiest choice, whereas with higher quantities or in cases where space is limited, a custom designed wiper might make more sense. One application might require a spring-loaded screw, while another will require a spring-plate attached to a piece of POM/Delrin plastic. Each application is specific to the requirements of installation space, cost and accuracy.

典型的膜电位器仅是剃刀薄0.5mm厚，宽度为8至12mm，长度高达760mm。

如果生命周期要求很高，建议使用磁力擦拭器以无接触式连接。然而，对于大多数应用，球形刮水器将会做。典型的刮水器占据有效宽度的约10％至50％。钢，黄铜和硬塑料（例如Delron，Delrin）等材料是典型的，但取决于膜电位器的类型。具体制造商应该能够提供有关正确选择的建议。

Different surface pressures are defined depending on the application, but in general, a range of 1 to 6 Newtons (N) is recommended for most applications, depending on whether the membrane potentiometer is configured in a standard foil layout or in a hybrid version with additional metal bonds to strengthen the structure. A standard off-the-shelf wiper is usually divided between a 1 to 3N and a 3 to 6N range.

电气特性
The electrical characteristics will vary somewhat with the design, but are generally the same as standard mechanical potentiometers. That is, they have a similar output to that of a conventional potentiometer acting as a voltage divider. So for instance, if there is 5V across a potentiometer and the position of the wiper is in the middle, the output signal would be 2.5V. As the wiper moves up and down, the voltage will change. This analog signal can then indicate the position of the wiper.

与传统的精密电位器相比，最显着的差异是实现线性度的方法，这是理论或计算的输出电压与实际输出电压之间的差异。因此，对于标准线性电位器提供的典型线性度为2％，尽管基于FR4的膜电位计可以达到0.5％。

虽然传统电位计可以使用激光修剪以实现基于PET材料的线性，膜电位器，依赖于生产改进以提高线性。最重要的生产改进是提高电阻油墨的均匀性，确保在整个印刷电阻墨水是均匀的。这可以通过根据电阻墨水的粘度调节丝网的网状尺寸来完成。

比线性更重要，是可重复性和滞后。膜电位计的精度可以高达0.01mm，长度为500mm，但大多数标准膜电位器范围为0.05mm至0.1mm。对所有电输出的主要影响是在刮水器的机械运动和稳定性中找到的。作为基准测试，能量耗散高达1W和500V的介电强度是标准的，其隔离强度也可能。

Applications
可以使用膜电位器来解决许多位置感测应用。一种改进的设计，在运动装置旁边产生线性输出信号，有时可以通过远离所测量的实际运动的齿轮连接的传统旋转电位计可以提高精度。虽然常规的机电电位器是成本强烈的，但膜电位器可以显着降低成本。

A typical application, due to the small height of membrane potentiometers, is the linear measuring of actuators. Control valves are another application, in which currently the standard requires gears and a turning sensor to measure position. The structure required to install and use a membrane potentiometer is simpler than those used in the large and difficult mounting of certain conventional potentiometers.

在许多应用中，旋转和线性膜电位器都可以在同一装置中使用。例如，座椅电平调节需要线性运动，而倾斜座椅靠背角度需要旋转运动。在汽车内饰中发现了类似的应用，其中滑动门，太阳屋顶等需求需要小安装空间和低重量。

空间问题的另一个简单解决方案是使用已经存在于许多应用中的PCB（印刷电路板），作为膜电位器的底座。可以填充印刷电路板，然后，膜电位器可以粘附到电路板中，并将连接器直接插入PCB。

使用膜电位器的其他应用主要用于节省成本的原因，是串 - 盆或电线传感器和磁带。另外，膜电位器可以完全集成到键盘中以进行手动控制。根据标准电位器的需要，集成电位器可以避免安装孔，并且可以采用完全密封和可清洗的前面板表面。

在工程交流中讨论这一点：