wave form in the transistors q 1 and q 2 in this way the switching is made to occur at the zero crossing of the current wave form in q 2 and as seen in the next cycle the reverse switching occurs at the zero crossing of the current wave form in q 1 thus this invention provides a linear oscillator which includes in the feedback loop a pair of switching transistors whose switching time is controlled by the linear oscillatory wave form it should be understood that in prior switching circuits the current was not zero and that power dissipation occurred in the transistors q 1 and q 2 during the switching transients based upon the average voltage and current during the switching transients for a time equivalent to the switching time of the transistors q 1 and q 2 it should be noted that in the circuit of this invention the frequency of operation of the circuit is determined by one resonant circuit which includes the transducer 47 and inductor 46 and that the phase of the switching between the current and voltage of the transistors q 1 and q 2 are precisely controlled because the voltage is switched based upon a signal proportional to the current flowing in such transistors it should be noted that changes in temperature and other effects which may vary the resonant frequency of the circuitry while effecting phase relationships between voltage and current in various parts of the circuitry would not effect the phase relationship between the switching time of the current and voltage in the transistors q 1 and q 2 because of the novel circuitry of this invention as a.