IEEE Solid-State Circuits Magazine - Summer 2016 - 20

Not having long-term plans allowed me to
follow my nose and take advantage of many
serendipitous events that crossed my path.
perfect summer job through a federal
program for students who graduated
at the top of their high school class.
Sandra Greer and Bob Hocken at the
National Bureau of Standards (NBS,
now called NIST) were looking for
someone to be a lab tech and chose
me for the job. It turned out to be an
almost perfect position for me. With
their help, I learned how to build
many different types of digital and
mixed-signal test equipment, which
just fueled my desire to continue to
break and make.
To be honest, the job didn't start
out that great. They had a list of projects that they wanted me to complete
over the summer, such as building
a dolly or wiring up cables; none of
them seemed that interesting to me.
But a job is a job, and within a couple
of weeks, I had built everything on the
list. At that point there wasn't much
more for me to do. I wanted to learn
about the types of measurements

that were being made in the lab,
which my hosts were happy to do,
but they were busy doing their jobs,
so they couldn't spend all their time
talking to me. Probably to get me out
of their hair, they suggested that I
spend time in the NBS library. While
I felt a little guilty getting paid to
read about stuff I was interested in, I
spent a lot of time that first summer
reading electronic trade rags in the
library. These magazines had tons
of interesting articles about building
different circuits, and while I really
didn't understand how the analog
designs worked, there seemed to be
circuits that might help my sponsors
do their research.
I worked in the Equation of State
section of the Bureau, which required
accurate temperature control, sometimes to sub moK, and very precise
measurements of capacitance, resistance, or voltage. I learned a great
deal about precision measurement

Figure 6: The fabrication tools that I used at nBS. The red object at the bottom of the photo
is a wiring pencil I used to build almost all my projects at nBS, and an extra spool of the
wire is shown above it. The insulation of the wire would melt/burn at solder temperatures.
The nontemperature controlled soldering iron that I used is also shown in the photo.

su m m E r 2 0 16

IEEE SOLID-STATE CIRCUITS MAGAZINE

systems. These were almost always
ac bridge circuits to avoid 1/f noise
issues and also allows you use amazing six-decade autotransformers, in
which you can control the ratio to a
part in a million, and lock-in amplifiers to measure error signals down
to nV. By the end of the summer I had
learned enough to build small electronics projects that helped them do
their measurements. For example,
one device allowed them to program
40 small resistor changes down to
the mX level for the precise setpoint
control of a temperature loop. This
replaced someone (me) going down to
the lab each day to update the resistance to change the temperature.
By the end of my first summer, I
decided that I wanted to build a digital filter for one of the very precise
5.5 digit voltage meter (DVM) that
was used in the lab. Since there were
no computers to take data back then,
they connected the output of the last
few digits of the DVM to a digital-analog converter and then plotted the output on a strip plotter. But the noise on
the measured signal was so large that
it was hard to read either the meter
or the chart. I thought a digital filter
could average the data without affecting its accuracy and make the data
much easier to read. No one thought
it was a good idea but me. They saw
a very complex project that was not
likely to work or make much of a difference in the measurements.
After much badgering (I can be
persistent), they gave in and allowed me
to give the filter a try. To build it, I used
a wiring pencil since wire wrap was too
expensive for us. The pencil dispenses
a very thin wire with insulation that
burns off at solder temperatures, and
I have used it ever since (see Figure 6).
After frantically working to get it done
before summer was over, I was able
to complete the filter before I started
school, and I can still remember how
happy I was when I got it to work. (This
was another example of where fate
smiled on me. After taking some digital
design classes at MIT, I realized that the
circuit contained a self-resetting loop
that generated a very small pulse. That

Table of Contents for the Digital Edition of IEEE Solid-State Circuits Magazine - Summer 2016