The quasistatic technique used to obtain MOS capacitance voltage characteristics and interface‐state density is finding increased use. While the basic technique has been described, it is felt that a detailed description of the apparatus setup and measurement technique will prove useful. This technique allows the rapid evaluation of MOS properties with accuracy of about 1 × 1010states/cm2eV near midgap. Experimental considerations such as MOS geometry, sweep rate, stray light, and series resistance, and their influence on the resultingC‐Vcharacteristic, are discussed.