Soldering (see RoHS), has led to a change in formulation of both solders and fluxes. Water-soluble non-rosin-based fluxes have been increasingly used since the 1980s so that soldered boards can be cleaned with water or water-based cleaners. This eliminates hazardous solvents from the production environment, and from factory effluents. Those regulations have also reduced the use of lead based solders, and caused the melting temperatures of solders in use to increase by up to . "Hot-bar reflow" is a selective soldering process where two pre-fluxed, solder coated parts are heated with heating element (called a thermode) to a sufficient temperature to
C-element by Varshavsky et al. Semistatic C-element stores its previous state using two cross-coupled inverters, similar to an SRAM cell. One of the inverters is weaker than the rest of the circuit, so it can be overpowered by the pull-up and pull-down networks. If both inputs are 0, then the pull-up network changes the latch's state, and the C-element outputs a 0. If both inputs are 1, then the pull-down network changes the latch's state, making the C-element output a 1. Otherwise, the input of the latch is not connected to either formula_4 or ground, and so the weak inverter dominates