Patent EP1238715 (http://l2.espacenet.com/dips/viewer?PN=EP1238715&CY=gb&LG=en&DB=EPD)
Post 247296 (https://www.thevespiary.org/talk/index.php?topic=6559.msg24729600#msg24729600)
(hest: "Re: initiating Grignards with ultrasonic ...", Chemistry Discourse)
The power supply transforms conventional 50/60 Hz electrical power into high-frequency electrical power at 20,000 Hz.
Power supplies are typically rated in watts of output power. It should be noted that using a power supply with a higher wattage rating does not mean that more power will automatically be transmitted to the liquid. Rather, it is the resistance to the movement of the probe (horn) that determines how much power will be delivered into the liquid. Load is determined by three factors: sample volumes, sample viscosity, probe size; and, in some cases, a pressurized environment. Under identical loading conditions, the wattage delivered by two power supplies with different power ratings will be the same (provided both have sufficient power capability).
The speed control on an automobile, can, to a certain extent, be compared to an Ultrasonic Processor. The speed control is designed to maintain the vehicle rate of travel constant. As the terrain changes, so do the power requirements. The speed control senses these requirements, and automatically adjusts the amount of power delivered by the engine, in order to compensate for these ever-changing conditions. The steeper the incline, the greater the resistance to the movement of the vehicle, and the greater the amount of power that will be delivered by the engine, to overcome that resistance.
The amplitude control allows the Ultrasonic vibrations at the probe tip to be set to any desired level. Although the degree of cavitation required to process the sample could readily be determined by visual observation, the amount of power required cannot be predetermined. Asensing network continuously monitors the output requirements, and automatically adjusts the power to maintain the amplitude at the preselected level.
Negligible power is required to keep an Ultrasonic probe resonating when operated in air. The greater the resistance to the movement of the probe due to higher viscosity, deeper immersion of the probe into the sample, larger probe diameter, or higher pressure, the greater the amount of power that will be delivered to the probe. Setting the amplitude control fully clockwise will not cause the maximum power to be delivered to the sample. The maximum power any Ultrasonic Processor is capable of delivering is only delivered when resistance to the movement of the probe is high enough to draw maximum wattage.
This phenomenon can be demonstrated as follows:
Depress a probe down against a piece of wood while observing the power monitor; as the down pressure (resistance) is increased, the amount of power delivered by the power supply will increase accordingly.
taken from:
What are ULTRASONICS and ULTRASONIC PROCESSING?
http://www.sonicsandmaterials.com/Accessories/accessories_8/technical/sonics%20white%20papers.pdf (http://www.sonicsandmaterials.com/Accessories/accessories_8/technical/sonics%20white%20papers.pdf)