For safety reasons, these analog sensors are packaged in the Tube. It is important to protect analog sensors by packaging them in 20-TSSOP (0.173, 4.40mm Width) packages. It is necessary for proper operation of this sensor to have 20 pins. In the DC circuit, this sensor should provide the maximum voltage of 5.5V. A magnetic switch may provide a minimum DC voltage of 3V in a DC circuit, however. During operation, the analog sensors could supply a voltage of 5.5V. There are 20 pins on it.