571

The Tektronix 571 is a curve tracer. It can show the characteristic curves of PNP and NPN bipolar transistors, both N- and P-channel FETs, diodes (including Zener types), and SCRs. It is a microprocessor-controlled device, and user interaction is done through navigation keys. A typical sweep run takes about five seconds. It has a parallel printer output that can print graphics on Epson-protocol dot-matrix printers.

Manuals – Specifications – Links – Pictures

One nice feature of the 571 is its ability to store a set of reference curves, which are displayed as a background for subsequent measurement runs. This makes comparison and matching between devices easy.

The 571 has a well-designed field of parallel-connected sockets to accommodate many different semiconductor package types. Details can be seen in the photographs below.

Because the nature of electronic component testing involves exposing components to sometimes hazardous voltages and operating conditions, at certain settings the 571 will refuse to start a measurement cycle until the user lowers the built-in hinged plastic shield over the socket area. 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.

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.

Key Specifications

Collector Sweep	0.5 V to 50 V (both polarities) with 2 A drive, 0.5 V to 100 V with 1 A drive
Vertical Display	plots collector current from 5 μA per division to 200 mA per division with 2% accuracy
Horizontal Display	plots collector voltage with 2% accuracy
CRT	raster scan, 640x336 resolution, monochrome, magnetic deflection, CRT made by Philips
Line voltage	100 to 240 VAC, 50 or 60 Hz
Power	240 W max − Actual consumption based on transistor being tested
Size	(W/L/H) 14.6" × 13.8" × 8.1"
Weight	9 kg (19.8 lb)

Pictures

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  571, front 3/4 view

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  571, rear view

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  571, measurement head, shield up

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  571, measurement head, shield down

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  571, parameters screen

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  571, run of a 2N2222A transistor

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  571, run of a 1N3020B 10V Zener diode

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  571, inside view

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  571, inside view, closeup of socket board

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  571, inside view, closeup of relays

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