| 摘要 |
PURPOSE:To predict the contamination of a record disc, by providing an electrode which measures the induced voltage of static electricity and a device which displays whether said voltage exceeds a specified voltage value or not with a meter or LED. CONSTITUTION:An electrode 1 is moved freely around a fulcrum 5 over a record disc 4 without contact with said disc, so that the positive or negative electric charge charged electrostatically on the record disc is induced to the electrode without contact. The differentiated value thereof is conducted as current i=dQ/ dt to an operational amplifier 2, and the quantity thereof is displayed with a meter or LED. Whether the induced voltage exceeds the normal value or not is displayed with the meter or the LED, whereby the contaminating state of the record disc is predicted. |
