Silicon Wafer Traffic Loop Detector Chips - 4 inch, Silicon Systems, Inc. (SSI)

About this Artwork: Silicon Systems Inc. (SSI), was a semiconductor company based in Tustin, California. SSI specialized in manufacturing mixed-signal integrated circuits and semiconductors, and catered to industries such as government, telecommunications, and data storage. This silicon wafer was fabricated by SSI in 1989, and contains SSI Traffic Loop Detector (TLD) chips. These chips are used in traffic signal control systems to detect the presence of vehicles. When a vehicle either passes over or halts within the detection zone of an inductive-loop detector (a wire buried in the road), it causes a reduction in the loop's inductance. This change is detected by the TLD chip as a drop in frequency, which prompts it to transmit a pulse to the control system, indicating the movement or presence of a vehicle. The wafer has about 850 TLD chips on it. Adjusted for inflation, the price per chip would be about $20, giving the wafer a value of about $17,000. About Making Computer Chips: Compu