An Improved ac Power Switch

Turning ac power on and off isn't always as simple as it seems. Here's an ac power controller that is safe, reliable, long-lived, digitally controlled, and interference-free. EARLY EVERY TEST SET includes a device to apply ac power to the unit under test. It may be a commercially available unit, but more commonly is specially built. It is normally a box containing a power supply, a relay, and a relay driver. Some of the fancier ones include inductors to enhance the life of the relay contacts...

Extended Memory and Modularity Are Added to the Series Computer Family

HP's newest Series 80 computers, the HP-86 and HP-87XM, provide memory capacities up to 640K bytes, different combinations of built-in interfaces, and for the HP-86, a modular system configuration, by John T. Eaton, Andrew W. Davidson, and William R. Frolik IN 1980, HEWLETT-PACKARD introduced the HP-85, the first member of the Series 80 computer family.1'2 It was designed to aid the scientist or engineer in collecting, analyzing, storing and displaying data. With its own internal tape drive,...

Low Cost Plotter Electronics Design

Eflement and Peter L. Ma f HE ELECTRONICS for the 74 70A Graphics Plotter had to be designed as inexpensively and ruggedly as possible to remain consistent with the philosophy of a low-cost, high-performance, high-reliability product. The basic guidelines for the design were to use a single printed circuit board for the entire electronic system, minimize overall parts count, eliminate the need for a cooling fan, and use custom and semicustom electronics with high...

Controlling a Graphics Plotter with a Handheld Programmable Calculator

Coverstone THE ADVENT OF THE HP-fL Hewlett-Packard Interface Loop transformed the HP-41C from a programmable calculator into a true computer system with mass memory, a variety of printers, and a video display. However, one capability still lacking was some form of graphics output. The HP 747DA Graphics Plotter with an HP-IL interface and the HP 82184A Plotter Module Fig. 3 was developed to satisfy that need. As a computer, the HP-41C possesses a powerful and...

Plotter Drive Motor Encoder Design

Johnson The 7470A Graphics Plotter uses dc motors for pen and paper positioning and optical encoders tor position feedback To achieve good graphic output at a low cost, the plotter drive system requires encoders with the following capabilities Two-channel output for determining direction 500-line count per channel 500 r min maximum motor speed 25 degree phase accuracy per channel. In addition to these requirements, the 7470A project design team had two main...

Graphics Plotter Mechanical Design for Performance and Reliability at Low Cost

Petersen, Chuong C. Ta, David C. Tribolet, and Robert J. Porcelli THE MECHANICAL DESIGN of a graphics plotter is a major factor in determining the plotter's cost, performance, and reliability. Although digital electronic techniques can replace the majority of mechanisms such as cams, springs, dashpots. and limit switches used in earlier plotters for control functions, paper handling and pen positioning must still be done mechanically. The plotting and pen...

Custom IC Electronics for a Low Cost Plotter

It was apparent eariy in the development of'he 7J70A that there mas a need to integrate much of trie electronics. The digita. portion most readily lends itself to integration in some form of custom IC The anatog circuits, on the other hand, were designed with off-the-shelf parts, but nevertheless benefited from the use of commercially available tCs In deciding which part of the digital electronics should be made into a custom IC. we noticed that the microprocessor, memory. I O controller and...

By Timothy V Harper

THE CP M OPERATING SYSTEM is the basis for some very well written software to help make your computer more friendly and useful. To make it possible to use this software in the HP-86 and HP-87XM Computers. Hewlett-Packard developed the HP 8290UA CP M System Module. The main focus of the 829QQA design project was to develop a simple, cost-effective solution to providing CP M capability and still have the power of the host computer available. The 82900A CP M System Module is easy to use. The...

Manufacturing Team in the RD

A manufacturing team was formed ear1 in the tab prototype phase of the 747GA Grap cs Plotter project and became an integral oart of the development effort. Its primary responsib uty was to influence the product assign for improved manufagtur-abiiity. This team developea the processes, machines, tooling, and test fixtures for the fabrication assembly and testing of the 747QA. The manufacturing team established a set of eleven objectives Tre primary objective coincided with that of the...

Index

Kathryn Y. Kivinn, Robert M. Hnllissy, and Roger E. Ison Data Communications for the 9826A and 9836A Computer Systems. Carl M. Dierschow and Robert P. L'hlrich Laser Printing System Provides Flexible, High-Quality, Cost- Effective Computer Output, James A. Hall Six Steps to a Printed Page, Robert F. Hay Laser Printing SyEtem Architecture, James T. Langiey Interactive Software for Intelligent Printers. Kathleen A. Fitzgerald Electrostatic Image Formation in a...

An improved ac Power Switch by Raymond A Robertson A novel combination of solidstate switches and mechanical relays

WWtETTMC K D D JUL n N At Our cover suggests a potential airfoil design application for two of this month's featured L products, the HP-86 Personal Computer and the 7470A Plotter. We're grateful to Pterodactyl, Ltd. of Watsonville, California for their help with the photo. Their original design calculations were done with an HP-35 Calculator. jjl The HP-86 and the HP-87XM, two new members of HP's Series 80 personal computer family, are the subjects of the article on page 3. These computers...