An is a closed path formed by the interconnection of electronic components through which an electric current can flow. The electronic circuits may be physically constructed using any number of methods. Breadboards, perfboards or stripboards are common for testing new designs. Mass-produced circuits are typically built using a printed circuit board that is used to mechanically support and electrically connect electronic components. The majority of the circuits can be built with readily available discrete components. Only a few of the circuits rely on microprocessors. Micros can greatly enhance the power of a small circuit, but the specialized development tools can put the project out of reach of many hobbyists. Electronic circuits can display highly complex behaviors, even though they are governed by the same laws of physics as simpler circuits. Electronic circuits can usually be categorized as analog, discrete, ormixed-signal electronic circuits.



? Analog electronic circuits are those in which signals may vary continuously with time to correspond to the information being represented. Electronic equipment like voltage amplifiers, power amplifiers, tuning circuits, radios, and televisions are largely analog.

? In digital electronic circuits, electric signals take on discrete values, which are not dependent upon time, to represent logical and numeric values. These values represent the information that is being processed. The transistor is one of the primary components used in discrete circuit, and combination of these can be used to create logic gates. These logic gates may then be used in combination to create a desired output from an input.

? Mixed-signal or hybrid circuits contain elements of both analog and digital circuits. Examples include comparators, timers, PLLs, ADCs, and DACs.

? Energy source - converts nonelectric energy into energy. Examples are batteries and generators. ? Output device - uses electric energy to do work. Examples are motor, lamp, or display.

? Connection - allows electric current to flow. Examples are wire and cable.

Electro-coating, referred to as electrode position, electrophoretic deposition, or electro painting is an organic finishing process that uniformly applies thin-film primers and one-coat finishes to metallic substrates. Electro-coating is based on the fundamental physics principle that opposites attract. The metal parts are charged with direct current and then immersed in a bath that has oppositely charged paint partials in it. This allows every corner, crack, and crevice to have a continuous even coating over the entire surface of the part. The direct current is controlled to allow the paint solids to build up to the desired film thickness. Once the part builds up the desired thickness it then acts as an insulator to stop the deposition process.

The process may be anodic or cathodic, depending on the charge applied the substrate. Although the processes are virtually the same, properties of the resultant coating are dissimilar. Anodic systems, which were the first to be used for electro coating, apply paint to positively charged substrates. The negatively charged pigment and resin particles deposit onto the substrate (anode). Cathodic electro coating deposits paint onto negatively charged substrates and offers several advantages over anodic electro coating. After the electro coating process is complete, excess paint is removed from the substrate by immersing or spraying the part with a permeate rinse (consisting of the ultra filter permeate of the e-coat bath itself) and then a DI water rinse. The rinse is collected and separated to recover paint and recycle a portion of it back to the electro coating bath.

The major advantages are environmental and economic which are:

1. The ability to coat complex surfaces evenly and allowing end users to maximize performance and minimize costs.

2. Elimination of drips, runs, and sages.

3. Closed loop rinsing and filtration allows transfer efficiencies of greater than 95%, with dramatic reductions in wastewater streams.

4. The Electrocoat technologies are formulated to be free of heavy metals, so there is very low level of Hazardous Air Pollutants.

5. Low level of organic solvents.