Abstract: A metal base (1), and holes (12) therein, of a printed circuit board are given an insulating coat (2) produced from an epoxy compound in particulate form which is deposited and machined successively at either side. An insulating topology (16) in a photoresist imposed on the insulating coat (2) is metal-plated in vacuum. On removing the metal from the prominent portions of the topology (16) tracks (4) and connecting pads (5) of a layer (3) of conducting pattern are left. An insulating topology (18) consistent with the disposition of connecting pads (11) and connecting posts (10) interconnecting the layers (3, 6) of conducting patterns is formed and metal-plated. On removing the metal from the prominent portions an insulating layer (9) with connecting posts (10) and connecting pads (11) is left. Next, an insulating topology (19) consistent with the topology of the layer (6) of conducting pattern is formed and metal-plated.

Abstract: A method comprises complete liquefaction of the cooling agent, before its cooling is carried out, by dissolving in the components of the mixture liquefied at the working pressure, those of which are in the vapor phase at the working pressure. The cooling agent includes difluorodichloromethane in the amount of 10-50 vol. %, component a having a normal boiling point within the range from -55.degree. C. to 85.degree. C. in the amount 10-50 vol. %, a component having a normal boiling point within the range from -30.degree. C. to 55.degree. C. in the amount of 10-50 vol. %, and a component having a normal boiling point within the range from 16.degree. C. to 35.degree. C. in the amount of 10-75 vol. %. The use in home refrigerators of the cooling agent of the present invention considerably increases maximum specific cold capacity of the refrigeration unit.