Abstract: A protection circuit and method for preventing high word line voltages during plasma processing of integrated circuits. The protection circuit includes a shunt transistor connected between each word line and ground, and a light sensitive element connected to the gate of each shunt transistor. During plasma processing, the plasma glow activates the light sensitive element, which generates a corresponding voltage that is applied to a gate of the shunt transistors. Consequently, the built-up potentials in the word lines are shunted to ground throughout the plasma process.

Abstract: An optical recording and/or reproducing apparatus employing a stepping motor for driving an optical pickup for movement in radial directions of a disk. The frequency of a driving pulse signal for driving the stepping motor is lower than the resonant frequency of a transmission system for transmitting the driving force of the stepping motor to the optical pickup and higher than the reproducing feed speed.