Increasing the coil current will increase the solenoid force and hence move the spool a greater amount against the spring.

增大线圈电流将加大电磁的力，因此推动阀芯压缩弹簧产生一个更大的位移。

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The resulting differential pressure is applied to the ends of the spool valve, raising it from its spring-centered null position.

结果导致滑阀端部产生差压并将其自弹簧中心电气零位提升。？

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Unfortunately, the Leica's take-up spool needs a long tapering tongue of film, which users must wedge under a spring clip on the spool's barrel before manually wrapping a few turns of film around it.

ECONOMIST: A die-hard analog photographer goes digital