User`s manual

7800 Series Hysteresisgraph System User's Manual
Introduction 1-1
CHAPTER 1
INTRODUCTION
1.0 GENERAL
This chapter provides introductory information for the Lake Shore 7800 Series Hysteresisgraph System.
Product description is in Paragraph 1.1, specifications in Paragraph 1.2, reference material in Paragraph 1.3,
safety summary in Paragraph 1.4, and safety symbols in Paragraph 1.5.
1.1 PRODUCT DESCRIPTION
The Lake Shore 7800 Series Hysteresisgraph measures the basic DC properties of permanent magnet materials in
bulk form. Major and minor magnetic hysteresis loops, remanence (B
r
), normal coercivity (H
c
), intrinsic coercivity
(H
ci
), and maximum energy product (BH
max
) can be measured. Other values such as permeance (load lines) and
knee shape (H
k
) can also be calculated. Sophisticated electronics and automated features simplify the measurement
process. Designed for research and development, quality control, and production-line testing applications, the
7800 Series Hysteresisgraph offers the most advanced and versatile tools for DC characterization of permanent
magnets on the market today.
1.1.1 Hardware Features
• High-resolution electronics with 20 to 24 bit analog-to-digital converters in all signal processing.
• Two Lake Shore Model 480 Fluxmeters for separate B and H channel integration. Both Model 480
Fluxmeters feature automatic drift compensation.
• Lake Shore Model 450 Gaussmeter with high-sensitivity Hall-effect probe for H measurements.
• Lake Shore Model 218 Temperature Monitor and Platinum RTD sensors for high-grade temperature sensing,
including milli-centigrade temperature display resolution (e.g., +20.152 °C)
• All signal processing is performed in low-noise, instrumentation-grade cases. Analog-to-digital cards inside
the PC case have been eliminated.
• All communication is digital via IEEE-488 Interface.
C780-1-1.xxx
Figure 1-1. Typical 7800 Series Hysteresisgraph System