直流仪表用变压器

direct-current telegraphy

speed conversion dc telegraphy (direct-current telegraphy)

direct-current telegraphy, compensating variations

direct-current telegraphy work (material) (rolling stock)

direct-current system【电】;straight flow system【航】

alternating current/direct-current

direct-current regulator using alternating polarization

restoring direct-current telegraphy