The purpose of the mains filter is to protect the load from line voltage surges and interference, as well as to prevent interference from the load itself from entering the network. Such a device consists of inductive, capacitive and non-linear elements.
Instructions
Step 1
Use a common grounding extension cord as the base for the filter. He should not have a switch. Make sure the extension cord is de-energized. Place the filter itself together with the switch in a separate plastic case between the plug and the extension cord.
Step 2
Take a two-pole switch rated for the mains voltage and current that will be drawn from the filter. Connect one of the mains wires to the switch input through a 10 A fuse, the other directly.
Step 3
Open a damaged computer power supply that has not been plugged in for over two weeks. Remove the board from it, and then carefully unsolder a special two-winding choke (do not confuse it with a transformer!), Which is located directly at the input (sometimes on the board, sometimes separately). It has two input and two output pins. Each of the input terminals is connected to the corresponding output through a winding. Connect one output contact of the switch to one input contact of the filter and the other to the other.
Step 4
Purchase a special three-pin arrester specially designed for use in 220 V line filters. Connect one of its side terminals to one input pin of the two-winding choke, the other to the other. Make sure to connect after the fuse and the switch! Connect the middle terminal of the arrester to the ground wire.
Step 5
Connect each of the output leads of the two-winding choke to its corresponding mains lead of the extension cord. Connect the grounding wire of the extension cord directly to the grounding wire of the plug. Make both grounding wires longer than the rest so that if the cord is accidentally pulled, they will come off last.
Step 6
Ring the input and output of the device to make sure there are no short circuits, regardless of the position of the switch. Insulate all connections carefully. Only then plug the filter into the mains and connect the load to it. Its power should not exceed the permissible for a two-winding choke.
