popular and their cost was quite reasonable. Today, like I
mentioned, the prices have sky-rocketed, probably from
lack of sales. As an interesting side note to this, about 10
years ago I had a design project that needed a high
powered resistive substitution box. I found one for sale
that was somewhat beat up but in working condition. It
covered six decades in one ohm steps with a tolerance of
1%, and was rated at 250 watts on any range. I haggled
and got it for $75. A month or so ago, I happened to see
a new one advertised for almost $2,000 (and I thought I
overpaid at $75!).
Next on the list should be a frequency counter.
Actually, a step up from this would be a universal counter.
This is a traditional frequency counter but also a period
counter (reciprocal of frequency). Plus, there are other
frequency related functions that extend its usefulness.
Here is a branch-off point, depending on where your
primary interests lie. I think an RF generator — even a low
grade one — would be an asset no matter which way you
go from here. Of course, I have already mentioned the
ultimate piece of equipment (the oscilloscope) which I
consider to be mandatory. If I was only allowed to own
one piece of TE, it would be a good scope. I consider this
as necessary as my right hand.
From this point on, the equipment needed will be
determined by the direction you desire to go: radio
frequency, logic circuitry, digital devices, robotics, and the
list goes on and on. Each discipline will have its own
specialized requirements for the TE needed.
As we acquire more skills and get deeper into any
specific area of electronics, the TE will also follow suit and
probably get more expensive. In one’s career span, the
birth of new technologies will spawn a need for
specialized TE that eventually will become useless many
years later when that technology is superceded by even
newer technology (analog TV and CRTs knocked out by
digital TV and flat screens, for example). The few essential
pieces of TE I have mentioned here will probably be
around for a long time, however, as they basically measure
the electrical properties of the science of electronics, and
that is law.
Although hand tools are not TE, they are an integral
part of the test bench, so I guess I should touch upon this
subject. There are a myriad of tools out there for old and
new technologies, with additional ones developed all the
time. As to surface-mount, the tweezer style test probes
are great, as are the tweezer soldering pencils. Beyond
that, everyone has their own favorite gadgets to get the
job done easier — even using tools that have no bearing
for SMD.
I use a set of old aluminum spring-loaded heatsink
clips to hold many of these devices in position for
soldering. In more conventional circuitry and through
hole, I generally only have a half dozen tools on the
bench: a pair of 3” needle nose pliers; a quality flush
cutter; a good pair of wire strippers; a few dental picks;
and, last but not least, a good surgical hemostat. I use a
fine-tip 35 watt solder iron for just about everything and a
bulb type solder sucker from RadioShack, which is the
most efficient type of sucker I have ever used (and it was
dirt cheap).
In closing out this particular discussion, I have to say
that the new “green” solder cannot even come close to
the good old Kester 37/63, which just flows and grabs so
much better. A good supply of random length clip leads
and a few cables terminated in various connectors (BNC,
SMA, F, etc.) are also mandatory items. These items will
just naturally accumulate as time goes by.
Purchasing Commercial
Test Equipment
When it comes to TE, there is just no substitute for
quality brand name equipment, and there are dozens of
top manufacturers out there. The only piece of TE I would
recommend buying as new would be a moderate quality
handheld DMM. All other top-of-the-line TE is just way too
expensive and out of reach for most of us. So, that leaves
us with buying used equipment; the go-to place here is
eBay. There are various other websites on the Internet that
handle used TE, so don’t neglect those. Also, if you are
fortunate to live near periodic government auction sales,
some incredible bargains can be had — sometimes as low
as $1 per pound if buying by the pallet. eBay does seem
to have a corner on the market as to TE sales, so I will
dwell mainly on purchases through them. Before I get into
specific equipment, I will walk you through a few general
guidelines for buying.
First thing I would recommend you do is to not buy
any equipment that is newer than vintage 1985. This may
sound strange to you, but there are good reasons not to.
From the late ‘60s through the mid ‘80s, there were big
design changes in transitioning from vacuum tube to solid-state equipment which rapidly improved over these years.
For sure, the ‘70s and ‘80s saw some marvelous TE
equipment produced by the big name manufacturers, and
a lot of it can still compete with newer equipment.
Then, enter the digital age from the late ‘80s and
onward. Older technology was now being replaced with
more up-to-date digital designs. Knobs and switches were
being replaced by buttons and membrane switch pads.
Features and accuracies were scaling upward at an
accelerated rate. This was all fine and good — to a point —
but had a lot of drawbacks for the home laboratory style
of electronics.
Along with all the improvements going sky high, so
were the prices. The cost alone for a lot of this TE even on
the used market is enough to drive you away. Also, the
operation of all this equipment was becoming more
complex due to the multitude of features now included. If
you do end up purchasing a lot of the newer TE, you will
probably end up paying for a lot of features you will never
use and/or never understand their use to begin with.
24 October 2015