Theory and Method
The QEC-Series measures mass by electromagnetic force compensation, the method behind every high-resolution analytical balance. A sample placed on the pan pushes the weighing system down, and a position sensor detects that small displacement. The balance then drives current through a coil seated in a magnetic field, and the coil produces an opposing force that returns the pan to its original position. The current needed to hold that position is proportional to the sample's weight, so the electronics convert it directly into a mass reading.
The QEC-Series adds a dual weighing range to this principle. Within the fine range (30 g, 50 g, or 80 g depending on model), the balance resolves mass to 0.01 mg for small or critical samples. Above the fine range and up to full capacity, it reads to 0.1 mg. Splitting the range this way delivers semi-micro resolution where it matters while still accepting loads up to 100 g or 200 g.
Stability at the 0.01 mg level depends on a quiet measuring environment. Temperature and humidity conditioning before delivery reduces drift from thermal expansion, the anti-static treatment limits charge build-up that would otherwise tug on light samples, and the sealed draft shield blocks air currents. Calibration ties the reading to a known reference: external-calibration models use an applied test weight, while internal-calibration models carry a motorized weight that the balance applies on command or on a schedule.
