Joseph Gorley's blog

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.