| 摘要 |
<p>A plating rate monitor includes a Wheatstone bridge, (24), one branch of which is a monitoring resistor (Rm) formed on a printed circuit board located in the same plating environment (26) as an object being plated. The resistor (Rm) undergoes plating at the same rate as the object. Each time the bridge (24) becomes balanced, another resistor branch (Rv) of the bridge, which is variable, is decremented by a preselected value to upset the balance. As the monitoring resistor (Rm) in the plating environment undergoes plating, a change in its resistance causes the bridge to become balanced once again and the time interval for achieving this balance, for a calculated plating thickness change of the monitoring resistor, determines the plating rate.</p> |
