Frequency Doubler

The wave form of the voltage induced in the control circuit, when the even-harmonics in the control current are suppressed, is comprised of even-harmonics of which the second harmonic (in terms of the a-c supply frequency) is the predominant one. The saturable reactor may be supplied with a third set of windings, one on each of the two cores, and connected with their polarities the same as the control windings as shown in Fig. 7-15. The even-harmonics in the voltage induced in the control circuit will also appear in that of the third set of windings, which supplies an L-C circuit tuned to resonance for the second harmonic and which serves as a supply of double-frequency power.

Figure 7-15. Frequency-doubling circuit