575

Manuals – Specifications – Links – Pictures

The Tektronix 575 is a curve tracer for transistors, introduced in March 1957. It can be thought of as being composed of three modules: an X-Y display, a step source, and a collector sweep source.

Key Specifications

Collector Sweep	0-200V Minimum Peak with 1A Current Curves, 0-20V Minimum Peak with 20A Current Curves,
Vertical Display	Plots Collector current from 0.01mA/div to 1A/div ±3% in 16 Steps
Vertical Display	Plots Base Voltage from 0.01V/div to 0.5/div ±3% in 6 Steps
Horizontal Display	Plots Collector Voltage from 0.01V/div to 20V/div ±3% in 11 Steps
Horizontal Display	Plots Base Voltage from 0.01V/div to 0.5V/div ±3% in 6 Steps
CRT	T52P, P1 Phosphor,P2/P7/P11 on request
CRT Accelerating Potential	~ 4kV
Line voltage	105-125V OR 210-250VAC 50 to 60 Hz
Power consumption	200W on Standby, 400W Max - Actual consumption based on transistor being tested
Size	(W/L/H) 13" × 24" × 16¾"
Weight	~30 kg (70 lb)
Cooling	AC Fan
Construction	Aluminum alloy chassis. Anodized front panel. Blue vinyl coated cabinet

History

John Kobbe says:

While I was working on the 540 series vertical amplifier, Virgil Briton, whose bench was next to me, had put together a vacuum tube curve tracer using stepping relays and other mechanical devices. I remember thinking that, that was a neat display even if it did a lot clicking and was slow. After putting the cross hatch generator together, I knew it would be very easy to do the curve tracer electronically,it started for in house use,but after putting a self-contained instrument together, Tek decided to call it 575 and sell it.

Internals

X-Y display

The vertical and horizontal amplifiers are very similar, using the two halves of a 6CG7 dual-triode tube as the output amplifier. The CRT has -1700 V on the cathode and +2500 V on the anode. The HV power supply uses two 5642 rectifier tubes.

It is possible to use the 575 as an X-Y monitor. The vertical and horizontal range switches have settings for external input, at 0.1 V/div sensitivity.

Step Source

This uses a gated Miller integrator to generate controlled steps. The result is a staircase waveform, which generates different traces in the the family of I-V curves of the transistor.

Power Supplies

The 575 contains three separate power supplies:

• Main Power Supply using T601 (120-095 and, later, 120-0095-01),

supplying power to the amplifiers and step generator in the 575

• High-voltage, using T801, supplying the CRT voltages, +2300 V for the CRT anode and -1700 V for the CRT cathode
• Collector sweep, using T701 (a variac) and T702, supplying the collector current to the device under test

Collector Sweep

Power from the mains goes through an isolation transformer and a variac and is rectified by germanium diodes to produce the collector sweep voltage. The isolation transformer has two pairs of secondary taps, one for high voltage (0 to 200 V) and low current, the other for low voltage (0 to 20 V) and high current. The maximum power that can be delivered to the transistor in either mode is approximately 200 Watts.

575 with Mod 122C has extended collector sweep voltage to 400 V.

Rectifiers

Early 575 versions used selenium rectifiers. A kit for conversion to silicon diodes was available and is documented in the back of the manual.

The 575 has a thermal cutoff.

Type 175 High Current Adaptor

575 on top of a 175

The 575 can be paired with a 175 for high current device measurements.

Links

• "A Power Curve Tracer At Surplus Prices" by Dennis L. Feucht (PDF)
• Some Transistor Measurements Using the Type 575
• Tek 575 @ oscilloscopemuseum.com

Pictures

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  575 w/o Mod 122C

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  575 w Mod 122C

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  575 Test Panel

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  575 In a Cart

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  575 testing a tunnel diode

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  Bottom

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  Bottom Rear

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  575 Load Resistance Chart

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  High-Voltage Power Supply

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Schematics

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  Unmodified Collector Supply

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  Collector Supply Rectifier with MOD122C

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  Main Power Supply

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  Step Generator

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  Amplifiers

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  CRT Circuit