High Voltage 100A Active Load with Transient Capability (Part One)


As part of a pulsed energy project, I needed to test a rather large power supply to achieve the desired results (48V @100A). For those that are looking, that’s 5Kw. This article discusses the design & implementation of a hybrid static/transient load testing instrument. This allows static load testing with superimposed transient capability in a single instrument.

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GPS locking a Rubidium Time Reference

In this article, I’ll discuss the implementation of a GPS stabilized 10Mhz. reference clock. For my requirements, the rubidium clock is a Stanford Research FS-275, which can be phase locked to a 1 pps reference. This is further GPS stabilized by coupling a GPS time receiver 1pps sync pulse to the rubidium clock 1pps input. This is primarily for correcting long term drift in precision timing applications. The rubidium crystal will age at a rate ~5e-9 long term, which can be improved to ~1e-12 by using GPS lock.

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HP 11721A Frequency Doubler Lab Repair

I was looking for a cheap doubler and came across this unit from Korea. It took almost 6 weeks to get here, some sort of customs holdup. This doubler covers an input range of 50-1300 Mhz. My intent with this was to provide an external doubler for my HP8640B. This item was designed by Bob DeVries of HP.


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HP 8640B Signal Generator Lab Repair

HP 8640B Signal Generator Repair

S/N 2835A30360

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I’ve been looking for one of these puppies for awhile. I used one of these in my work in the mid-late 70’s, so I’ve been trying to find something broken but newer to bring back to glory. Considered by many as one of the finest signal generators ever manufactured, the 8640B has been around a long time, and its frequency stability and spectral purity is second to none.

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