Broad band saturable reactor regulated power supply

In a regulated power supply adapted for being connected to a constant line voltage and for providing a preselected, regulated voltage to a load having a variable power demand, and including a power oscillator circuit which converts the line voltage to a higher frequency voltage, an output circuit adapted for connecting to the load and providing the regulated output voltage thereto;

• a saturable reactor operative for modulating the higher frequency voltage from the power oscillator circuit, the reactor having a gate winding interconnected between the power oscillator and the output circuit and also having a control winding, a feedback control circuit connected between the output circuit and the saturable reactor control winding for controlling control winding current, in response to varying power demands of the load connected to the output circuit, said feedback control circuit comprising:
• (a) load current sensing means enabling said voltage modulation by the saturable reactor in response to load current fluctuations to thereby maintain said preselected regulated voltage to the load,
• said sensing means including a low resistance current sensing resistor, R.sub.1, connected in a control winding current in series with the said control winding;
• and
• (b) resistor means providing a phantom, control winding series resistance, R.sub.c.sup.*, which is at least several times greater than that of the current sensing resistor R.sub.1,
• said phantom resistance R.sub.c.sup.* causing a time constant, t.sub.c, of the control winding circuit to be much shorter, and hence response time of the saturable reactor to be much faster, than that which would otherwise be provided by only the resistor R.sub.1, undesirable power dissipation in the control winding circuit being, however, determined by R.sub.1 but not by R.sub.c.sup.*.