know I keep saying this, but it keeps being true so I say it again:
The basics of electricity and electronics have not changed in the last
50 or more years, so there articles from vintage issues of electronics
magazines are as applicable today as they were back then. If you are
just getting into the field of electronics, valuable information can
be found here to supplement your learning process. In fact, I have seen
examples in some of these articles where I re-learned something long-ago
forgotten, and some of the stuff is rarely, if ever, seen in contemporary
writings. Regardless, making yourself aware of the work done by pioneers
in the industry is always valuable because it gives you a sense of approaches
taken that have led to success, and sometimes failure on the way to
May 1967 Electronics World
of Contents] People old and young enjoy waxing nostalgic about
and learning some of the history of early electronics. Electronics World
was published from May 1959 through December 1971. All copyrights are hereby acknowledged.
Electronics World articles.
See all the available
Electronics World articles.
Tips for TechniciansCapacitor stability at bargain prices
Any capacitor changes its microfarad value when temperature varies.
And some capacitors change more than others. In some circuits, capacitance
drift with temperature can cause real problems.
at circuits where you have fractional microfarad values of paper, film,
ceramic or mica capacitors. During warm-up from room temperature to
65° C ambient, a capacitor with a temperature coefficient of, for example,
500 parts per million per degree C will increase capacitance value by
2%. This change is enough to cause troublesome drift in tuned circuits,
where inductance also increases with temperature. It can knock the accuracy
of a timing circuit off, or mess up the performance of a differentiator
network. For these applications, we have a new kind of capacitor that
beats anything we've seen in the stability race. It's the new Mallory
Polystyrene Capacitor. They're made of stretched polystyrene film and
high purity aluminum foil. The assembly is fused into one piece, with
the polystyrene forming a solid case of clear plastic that you can look
through and see the foil. Their temperature coefficient is less than
150 parts per million per degree C, which is about half that of polyester
film capacitors. And the coefficient is negative; capacitance goes down
when temperature goes up, compensating for the upward drift of inductance
elements in tuned circuits.
Want more? Mallory Polystyrene Capacitors
have the lowest dielectric loss ... only a small fraction of that of
other film capacitors. Their insulation resistance is way above that
of mica, film or paper capacitors. And the best part of the whole deal
is that they're really low in price!
There's something new from
Mallory, too, in stable electrolytic capacitors. It's the molded-case
MTA, which has temperature stability that beats most metal case types.
It has shown up so well on life test that manufacturers are using it
in instruments and computers. And while it's priced down with cardboard-case
tubulars, it beats them every way on quality.
You can get these
stable Mallory capacitors, and everything else you need for service
or experimenting, from your nearby Mallory Distributor. Ask him for
a copy of our 1967 General Catalog, or write to Mallory Distributor
Products Company, a division of P. R. Mallory & Co. Inc., Indianapolis,
DON'T FORGET TO ASK 'EM - "What else