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May 4, 1964 Electronics
 [Table of Contents]
Wax nostalgic about and learn from the history of early electronics.
See articles from Electronics,
published 1930 - 1988. All copyrights hereby acknowledged.
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We really have it good today compared
to the early days of the semiconductor revolution. Most of the most difficult problems
were solved long ago. Point contact devices were still fairly commonplace even in
1964 when this ad appeared in Electronics magazine. Recall that the very
first manufactured solid state diodes and transistors were the point contact type
that were encapsulated in glass with a space gap where the contact was made. That
left the device vulnerable to vibration and impact damage and to contamination if
the hermetic seal failed between the metal lead and the junction(s). Unitrode claims
to have been the first to eliminate that issue with essentially a fully bonded package.
Keep in mind, however, that even the early semiconductor device packaging was no
worse than the vacuum tubes that they replaced, since the tubes also suffered from
the same vulnerabilities due to their construction. In fact, the process used with
the early solid state device packaging descended directly from vacuum tube construction.
Unitrode Advertisement
 This is what diodes looked like before Unitrodes
Remember?
Remember the fragile whisker so easily burned out?
The cavity where, in time, contaminants were sure to degrade reverse characteristics
eventually? The delicate construction that was likely to fail under thermal and
mechanical stress? The limited service life even under the best of conditions?
Never again.
Unitrodes have changed all that with an entirely new approach to diode design.
The silicon wafer is high-temperature bonded directly between the terminal pins,
and a hard glass sleeve is fused to all exposed silicon. Result: a void-free junction
that can't be contaminated. Broad current-carrying surfaces that can withstand 10
watt power overloads - continuously - with no after-effect.
A one-piece unit indifferent to shock. vibration, acceleration ... unperturbed
by thermal shock or cycling from -195°C to +300°C.
Naturally you'd expect performance like this to cost a bit more, and it does.
Mainly because of rigid manufacturing standards and because every Unitrode" diode
is 100% final tested. But if you're working in high reliability, you owe it to yourself
to watch your Unitrode representative's 15-minute demonstration. We'd be happy to
send him around with our entire line of diffused 3 ampere silicon diodes, fast switching
rectifiers, 3 watt zeners, high voltage stacks and bridge assemblies. We never cease
to be amazed ourselves. Write or call ... Unitrode Transistor Products, Inc., 214
Calvary Street, Waltham, Massachusetts 02154, Tel: (617) 899-8988 TWX: (617) 894-9876.
Posted May 29, 2024
(updated from original post
on 5/28/2018)
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