What is a band switch?

Band switch, is a very old name. In fact, it should be called a multi-pole multi-throw switch, because it can be used not only as a band switch, but also for other purposes. As for how many knives (that is, how many sets of contacts) are needed, it depends on the needs of your circuit. Of course, at least two or more groups can be called band switches. As for how many toss (that is, how many gears) you need, it also depends on your needs. There are from 2 files to more than 10 files. If it is only used as a band switch, there are less than 4 sets of contacts, and at most 6 sets of contacts are sufficient. In terms of gears, as many bands as there are, you need as many gears, at least 2 gears. There are also various types of "band switches". The common ones are rotary, there are push-pull, and key (key) types. The volume is also large and small.

Why can't the frequency of the external potentiometer of the inverter be adjusted up?

A frequency converter, the operation panel can be controlled normally, and the adjustment frequency can also be changed from 0 to 50HZ, but with an external potentiometer, the frequency cannot be adjusted to 20HZ, what is the reason?

How to connect the three pins of the potentiometer?

A potentiometer is a resistive element with three leading ends and the resistance value can be adjusted according to a certain changing law. A potentiometer usually consists of a resistive body and a movable brush. When the brush moves along the resistor body, the resistance value or voltage that has a certain relationship with the displacement is obtained at the output end.