The Tektronix 370B Curve Tracer is the world standard for high resolution curve tracers. the Tek 370B provides up to 20 A / 2000 V sourcing capability combined with 1 pA and 50 μV measurement resolution. The Tektronix 370B performs DC parametric characterization of integrated circuits, transistors, thyristors, diodes, SCRs, MOSFETs, electro-optic components, solar cells, solid-state relays and other semiconductor devices. It has pushbutton source and measurement configuration so it‘s easy to change from one test to the next.
The Tek 370B is used in a wide variety of applications including:
Parametric Characterization of Semiconductors
Failure Analysis 
Data Sheet Generation
Manufacturing Test
Process Monitoring and Quality Control
Incoming Inspection
Component Matching
Features of the Tektronix 370B curve tracer include:
High resolution DC Parametric Measurements (Resolution Down to 1 pA or 2 μV) 
  Built in Cursor Measurements: Dot, Window and Function Line
Kelvin Sense Measurements
Sweep Measurement Mode
Waveform Comparison & Averaging
Fully Programmable
1.44 MB Floppy Drive Stores Setup and Bitmap of Curves
Direct Hardcopy with printer
Interactive Programmable Control
Interactive control of all 370B measurements is accomplished from the full-featured front panel or over the GPIB. Every operating parameter can be controlled using the GPIB controller. 370B Series LabView drivers are available at www.Tektronix.com. These drivers have many of the building blocks to create a custom measurement solution.
Store and Recall Setups and Digitized Curves
Up to 80 digitized characteristic curves can be stored on a diskette or in internal non-volatile memory and recalled at the touch of a button. A live curve can then be compared with a previously stored curve to assess temperature drift or other changes in operating parameters. To help identify the data, up to 24 characters of text may be used to label or annotate the curve data. Operating parameters can be adjusted, stored and recalled using several storage methods including the 370B system memory, the built-in 1.44 MB floppy drive, or sent externally via the GPIB controller.
Automated Cursor
The 370B provides three cursor measurement modes. The dot cursor provides direct screen readout of voltage, current, gm or DC beta at any point. The window cursor can be positioned between two curves to measure small signal beta or gm and can also be used for visual go/no-go tests. The function line cursor provides screen readout of a slope or intercept value.
Sweep Measurement Mode
In the sweep measurement mode, the curve tracer automatically constructs a family of curves. 
Direct Hardcopy Printouts
Curve output data can be sent directly from the 370B and 371B to a Citizen iDP-3240thermal printer. Printing can continue while the 370B and 371B perform the next tasks.
What is the difference between the 370A vs. the 370B?
The 37xB models use a 1.4M floppy drive which replaces the 720K drive on the 37xA models.
The 370B allows saving screen images to the floppy in .bmp format.........shift/hardcopy
The 370B allows saving curve files to the floppy in .csv format.............local/hardcopy
The 370B has a Centronics print port which replaces the GPIB