Radio Frequency Power Generators:

The majority of radiofrequency (rf) power generators are crystal controlled radiofrequency generators. These are designed to operate within the industrial frequency bands of 27.12 or 40.68 MHz, although plasma generators have been described operating at between 5 to 100 MHz. The radio frequency at which the torch operates is an important parameter in sustaining plasma operation. At the lower frequency range it is necessary to deliver large power up to 30 kW to sustain the plasma. At a frequency of 27.12 MHz, the generators are generally designed along with maximum power ratings of between 2 and 5 kW, and are often used routinely to deliver about 1 kW to the plasma. The radiofrequency power supply is so controlled that it ensures a constant power transfer to the induction coil.