Single lead displacement sensor

The invention discloses a single lead wire displacement sensor, and the single lead wire displacement sensor comprises a single lead wire, an iron core, a single coil, and an outer-layer metal housing. The iron core and the single coil are located in the outer-layer metal shell, and the outer-layer metal shell is used for protecting the single coil and connecting a circuit in an instrument to be tested; the single coil is wound outside the iron core according to corresponding preset coil turns in adjacent displacement intervals when the iron core is in different displacements, and the iron core is used for being connected with an instrument to be tested; one end of the single coil is connected with the outer-layer metal shell, the other end of the single coil is connected with a single lead, and the single lead is connected with a power supply. The problem that the displacement sensor cannot be installed due to the fact that a plurality of single leads need to be connected when the displacement sensor is inst