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This is to protect the user from both high voltage and high-velocity flying debris in the event of a catastrophic component failure during a test run. | This is to protect the user from both high voltage and high-velocity flying debris in the event of a catastrophic component failure during a test run. | ||
The shield is made of a thick high-impact plastic, and the 571 has an internal microswitch so its firmware knows if the shield is in the up or down position. | The shield is made of a thick high-impact plastic, and the 571 has an internal microswitch so its firmware knows if the shield is in the up or down position. | ||
==Internals== | |||
The Tektronix 571 is a computer-based instrument. | |||
Software running in an Intel 8048 microcontroller performs the I-V curve measurements | |||
by sending commands to programmable base and collector power supplies, | |||
and reading the digitized that results. | |||
Software provides the user interface, reading the buttons and generating the displayed bitmap. | |||
The 571 uses an National Semiconductor NS405 Display/Terminal Management Processor IC for generating the | |||
video waveform that is displayed. | |||
The video waveform is fed to a monochrome raster CRT monitor. | |||
===Collector Supply== | |||
The collector supply is a floating programmable power supply. | |||
The output voltage, output polarity, and series resistance are all | |||
controlled by bits sent by the 8048 processor. | |||
The collector supply is linear, using a Darlington configuration of three NPN transistors. | |||
==Specifications== | ==Specifications== | ||