Restriction of Hazardous Substances Directive a disadvantage because it can lead to lower quality electrical connections – can be used to place components more tightly than they used to be placed due to the properties of lead-containing solders. For example, Motorola reports that their new RoHS wireless device assembly techniques are "...enabling a smaller, thinner, lighter unit." Their Motorola Q phone would not have been possible without the new solder. The lead-free solder allows for tighter pad spacing. Research into new alloys and technologies is allowing companies to release RoHS products that are currently exempt from compliance, "e.g." computer servers. IBM has announced a RoHS
Electrical element defined by a relation between the state variables of the network: current, formula_1; voltage, formula_2, charge, formula_3; and magnetic flux, formula_4. In reality, all circuit components are non-linear and can only be approximated to linear over a certain range. To more exactly describe the passive elements, their constitutive relation is used instead of simple proportionality. From any two of the circuit variables there are six constitutive relations that can be formed. From this it is supposed that there is a theoretical fourth passive element since there are only five elements in total (not including the various dependent sources) found in