Abstract: A ferroresonant power supply having a relatively temperature stable output voltage includes a saturating magnetic element having a magnetizable core and a winding located thereon. A magnetizing current is developed in the winding by a high frequency source of alternating input voltage for generating an alternating magnetic flux in the magnetizable core that links the winding so as to develop an alternating polarity output voltage. A capacitor develops a circulating current that generates a magnetic flux in a core section associated with the winding that aids in magnetically saturating the core section to provide regulation of the alternating polarity output voltage by means of ferroresonant action. In order to temperature stabilize the output voltage, the magnetically saturating core section of the magnetic element is formed of a ferrospinel comprising a lithium ferrite or a substituted lithium ferrite.