Single-live-wire electricity-taking circuit and single-live-wire electricity-taking system

The invention relates to a single-live-wire electricity-taking circuit and a single-live-wire electricity-taking system. The single-live-wire electricity-taking circuit comprises a first electricity-taking module and a second electricity-taking module, the first power taking module comprises a first terminal and a second terminal, the first terminal is used for being connected with a front end point of a live wire line, and the second terminal is used for being connected with a rear end point of the live wire line; the second power taking module comprises a third terminal and a fourth terminal, the third terminal is used for being connected with the rear end point of the live wire line, and the fourth terminal is used for being connected with the zero line line; the first power taking module is used for taking power from the front end point of the live wire line and then supplying power to the first power utilization module when the voltage of the live wire line is greater than the voltage of the zero line li