The universal color coding of resistors does
not change, fortunately, but resistor body colors and the style
of wire leads can vary. Also, resistors may be packed loose or
supplied on tape strips. Install any resistor as shown on the PC
board parts layout diagram. Keep all leads as short as possible.
SEE THE RESISTOR COLOR CODE TABLE ON THE LAST
CERAMIC DISC CAPACITORS
It is helpful practice to become as familiar
as possible with the various marking codes for ceramic
capacitors. The first fact to keep in mind is that there are
several accepted methods for marking the value of these
capacitors! While resistor color codes have withstood changing
times over many decades, the protocols for marking evermore-tiny
capacitors have many variations!
While capacitors also can be color-coded,
Ramsey Kits use disc capacitors marked by a number-letter code.
The first two digits establish the first two numbers of the
value. The third digit is the multiplier. The letter designates
the manufacturing 'tolerance" or accuracy for the value
Values under 100 picofarads, used widely in
our FM and VHF kits, are printed clearly with no need to
interpret them further. Small capacitors stamped 4.7, 10, 15,
33, 68 and so forth are 4.7, 10, 15, 33, 68 picofarads
respectively! A 100 picofarad capacitor, also commonly used in
our kits, can be marked either 100 or 101! If it's marked 100,
believe it. If it is marked 101, the value is 10 (first 2
digits) X 10 (3rd digit multiplier) = 100 picofarads! If it is
marked 101J, we know that it is made to 5% accuracy, while H
signifies 3% and K is 10%.
Rule of thumb: If the 3rd digit is a 0, you
may assume the value is in picofarads, and you can take the
three numbers together as the pico-farad value for that
capacitor. So, just as in the above example, both
"470" and "471" are 470 pf.
There is a growing trend to mark capacitors
very clearly in nanofarads. Be sure not to confuse 10nf or 100nf
with 10 or 100 picofarads!
There's more! Some manufacturers don't care
about codes and print the value and tolerance VERY plainly.
E.g.,. "820+20%" means 820 pf. at 20% tolerance. Yet
another style of capacitor for values such as .1 uf is
manufactured as a neat, rectangular block, with the value and
other identifying data stamped on the top. For example, the
information of interest to you in the marking ".1J63"
on such a capacitor is the ".1" for .1 uf. SEE THE
CAPACITOR TABLES ON THE BACK PAGE OF YOUR KIT MANUAL!
Virtually every kit uses one or more
electrolytic capacitors. These are polarized capacitors, which
means that they have positive (+) and negative (-) leads and
MUST be installed correctly on the PC board. Your kit
instruction manual is very clear about correct polarity of these
capacitors, and the positive (+) side is generally etched on the
PC-board itself. Ordinarily, only the negative side is marked on
Coils or inductors supplied with Ramsey kits
can come to you in ANY of these styles:
||Enameled wire and easy
do-it-yourself winding directions
||Color-coded coil similar
in appearance to a resistor
Your kit manual provides clear information
for correctly identifying any coils used.
If a kit uses one diode, or a number of the
same kind of diode, you are in luck. Just be sure to understand
the difference between the cathode (banded) end and the anode
before installing. If the kit uses several different diodes, it
is necessary to identify each of them correctly. Believe it or
not, there ARE printed markings on even tiny diodes. You'll need
a magnifying glass even if you claim perfect 20-20 eyes! If you
are unsure about correct diode identification, please ask for
An LED (light-emitting diode) is indeed a
diode, not a lamp. If your kit uses LED's, the instruction
manual shows you clearly how to install them correctly. A
numeric display such as used in frequency counters or tone
decoders is a series of LED's.
The most common single transistor for most
Ramsey kits is the versatile NPN 2N3904. We use a variety of
other types as well. Please pay close attention to how the
"flat" or other special characteristic of any
transistor is oriented on your kit manual's PC-board drawing.
Many Ramsey kits employ at least one IC. And,
for most kits, we encourage careful, direct soldering of the IC
to the PC board. Our years of factory service experience shows
us that IC sockets themselves can cause needless problems. If
you prefer to use sockets, buy them and do so. Be very careful
in setting IC's into sockets. It is VERY important to orient the
end with the notch, ball or band in the direction shown on the
NON-CRITICAL PART VALUES
The majority of components in our circuits
have a specific value for a specific purpose. For example, a
certain resistor is needed to provide correct bias to a
transistor. And, of course, the frequency of tuned circuits is
directly determined by the capacitor and inductor. However, some
parts values are not critical at all, and your kit manual may
specify, for example, that an electrolytic capacitor may be in a
range of 2 to 5 uf or 4.7 to 10 uf. Or we can state a range of
values for resistors or potentiometers or that "any"
NPN transistor will work in a given circuit position.