POWER-SUPPLY SOURCE FOR ELECTROMAGNETS

A power supply source was developed for an electromagnet with a resist ance of 10 Ohm and an inductance of 30 mH, which is used for automated measurements of galvanomagnetic and thermomagnetic coefficients of se miconductor materials in a constant magnetic field, The source ensures a ''soft'' electronic turn-on, turn-off and polarity switching in reg imes of current or voltage stabilization. Current and voltage can be s moothly varied within 0-3 A and 0-30 V, respectively. The coefficient of stabilization is greater than 10(3), the double amplitude of pulsat ions is smaller than 1 mA, and the turn-on and turn-off delay time is shorter than 2 s.