Many different groups have established standards for modeling and testing electronic devices for their ability to tolerate ESD. The four major groups are shown here with their respective Standard Numbers and Testing Conditions. All use the ‘Human-Body Model’ comprised of a charged capacitor (C) in series with a resistor (R) discharging into the “Device Under Test”. They all use the same resistance and capacitance values, but vary with regard to the charged voltage level and whether it is a Contact Discharge and/or Air Discharge.