Basic Connections

Faceplate Image

The GND binding post is the reference point for all circuit traces. Both the Collector voltage and Base step generator currents return to this point. If your computer is plugged into an AC power outlet, then GND is also earth ground. Circuits with earth grounds through AC power outlets should be disconnected if nodes other than ground are used as a reference GND node. Do not connect to powered circuits and make sure all energy storage devices, such as capacitors and batteries, are discharged or removed before connecting a curve tracer. Safety First!

The COLLECTOR connects to the test node of a circuit or device that is to be characterized with respect to GND. The COLLECTOR binding post connects to the collector sweep voltage source through a series limit resistor (set with the rotary switch). It also connects to a voltage follower amplifier that is part of the measurment system. Attaching the COLLECTOR to a voltage greater than +18V or -18V could damage the amplifier.

The BASE connects to  a step generator that  provides current from +200uA to -200uA or voltage from +10V to -10V. The current or voltage is constant until programmed to a new value. The resolution is from the 12-bit DAC which has 4095 steps. The current changes 9.8nA/step and the voltage changes 4.88mV/step. The step generator connects to the control node of the device or circuit under test.

Image of completed box

The USB connector is located on the right side of the curve tracer box. A mini-USB-B to USB-A cable connector attaches the Mini-CT to a Windows operating system computer. Mini-CT has been tested on  XP, Vista, Windows-7 and Windows-8 computers.  Mini-CT requires a specical version to display correctly with Linux Wine.

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