Recent developments on magnetic-coupled multivibrators

In a static d-c to a-c converter employing a saturating transformer with rectangular-hysteresis-loop core material in conjunction with two switching transistors (magnetic-coupled multivibrators), the oscillation frequency is linearly proportional to the d-c supply voltage. This fact is significant with regard to telemetering-transducer applications. However, the linear relation between d-c input voltage and frequency of the square-wave output voltage is quite unfavorable in those cases, e.g., design of test circuits for magnetic amplifiers, where it is necessary to vary the oscillation frequency of the magnetic-coupled multivibrator independently, without changing magnitude of the supply voltage.