Tektronix introduced the industry’s first curve tracer in 1955 to display characteristic curves for vacuum tubes, followed over the years by models for testing transistors, diodes and other solid-state devices. Tektronix curve tracers such as the 576 (below) and 370A/370B went on to broad industry acceptance until production eventually stopped in the mid-eighties. Approximating a power supply and an oscilloscope packaged in the same box, curve tracers source voltage while plotting voltage vs. current.
