An adjustable current source comprises a choke (1) and a capacitor (2) whose reactive impedances are equal at the frequency of a variable voltage source (3), as well as a load current matching and adjusting unit made as a magnetic amplifier (4). Some outputs of the choke (1), the capacitor (2) and a primary winding (6, 7) of the magnetic amplifier (4) are coupled to respective phases of the variable voltage source (3). Other outputs of the choke (1), the capacitor (2) and the primary winding (6,7) of the magnetic amplifier (4) are joined in a star connection. The secondary winding (9, 10) of the magnetic amplifier (4) is coupled to the load (11). The control winding (13) of the magnetic amplifier (4) is coupled to a constant voltage source (14).