Vacuum Tubes as Power Oscillators

Chapter IV. The general method of designing any but the simplest of circuits is to draw a vector diagram and then calculate circuit constants that will give vectors of the proper lengths and directions. This method has been exemplified by designing a circuit in which the grid is tuned and contains the load. The plate circuit is magnetically coupled and is partially tuned to act as an harmonic by-pass. A numerical example of the method is given. Chapter V.-The criteria for double periodicity of two coupled circuits are first developed and it is shown that for a singly periodic circuit the secondary volt-amperes cannot exceed the primary. The maximum power which can be transferred to the secondary is limited by this requirement. A greater amount of energy can be transferred by a closer coupling, which results in making the circuit doubly periodic, and tuning the circuits individually to other than the desired frequency. High power will then be delivered on only one of the stable frequencies. The method of designing a circuit to deliver energy under such conditions is developed. Such a circuit always tends to oscillate at the frequency giving least load. It is shown that grid keying cannot be used without other modifications of the circuit.