About: http://webisa.webdatacommons.org/329530373

Property	Value
http://www.w3.org/1999/02/22-rdf-syntax-ns#type	http://www.w3.org/ns/prov#Entity
http://www.w3.org/ns/prov#value	A difficulty with these types of systems is the need to monitor relatively high line voltages or the need to change circuit elements such as capacitors and resistors to be able to vary the parameters of control.
http://www.w3.org/ns/prov#wasQuotedFrom	freepatentsonline.com