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This circuit is a semiconductor test device which plots the I-V characteristics of the DUT. At the moment, it supports small signal diodes and BJTs, and may be expanded to support FETs and high-voltage devices in the near future. It generates two signals: a step current applied to the base terminal, and a ramp voltage applied to the collector terminal. The output is a voltage proportional to the resulting emitter current, which displays the desired I-V curves when viewed with respect to the collector voltage - this can be readily done by using the X-Y acquisition mode on an oscilloscope.

The curve tracer has many practical uses in circuit design:

• Transistor matching
• Measurement of:
  • DC current gain
  • Base-emitter saturation voltage
  • Forward voltage

Related links:
» Schematic [pdf]
» GitHub [link]