TELE-TECH & - AmericanRadioHistory.Com

Nom!
A LOW COST
BRIGHT RHODIUM
PLATING PROCESS
for electronics and
electrical components
ea&
BRIGHT"
RHODIUM
PROCESS
//
At last ... a long sought
rhodium plating process
which provides all the desirable
characteristics of
rhodium plus many exclusive
features which makes
it particularly suited for
electronic and electrical
component manufacture.
Sel -Rex BRIGHT RHODIUM
deposits are mirror bright,
resistant to tarnishing and
corrosion, have excellent
conductivity and reflectivity.
Produces a hard surface
that is excellent for
sliding and wiping electrical
contacts where light
or heavy pressures and
low contact resistance are
required.
EXTRA! Sel -Rex BRIGHT
RHODIUM offers ASC -
Automatic Stress Compensation
- a special
technique which counteracts
the high stress characteristics
inherent in
conventional rhodium
plate.
Sel -Rex BRIGHT
RHODIUM used
extensively in
following
products
Printed Circuits
Connectors
%
Tubes
I\
',nave Guides
Switches
Reflectors
Sel -Rex Precious Metals, Inc.
229 Main Street Belleville 9, N. J.
Sel -Rex Precious Metals. Inc.
229 Main Street. Belleville 9.
TT-6
Please rush literature on Sel -Rex BRIGHT
RHODIUM and other famous Sel -Rex Plating
Processes.
Name
Company
Address
City
Zone
State
Eddy- Current Bridge
(Continued from page 359)
balancing operation. The potentiometer
setting is recorded as the
relative surface resistance of the
sample.
Good shielding is essential between
the driving and the pickup
circuits, since the pickup voltage is
perhaps five orders of magnitude
less than the oscillator voltage. For
runs greater than a few feet, doubly
shielded coaxial cable is advantageous.
Vibration of the head produces
a varying reactive unbalance,
hence rigid construction of the instrument
head is essential.
The crystal diode, although it introduces
appreciable nonlinearity
into the circuit, is used here because
of its simplicity. With this note,
Table II is presented. All the data
shown were taken with the circuit of
Fig. 3. The samples were not cleaned
to remove surface films but are in
"as received" condition with the exception
of the OFHC copper standard.
Instrument Heads
Fig. 1 shows the circular loop head
described, and also a linear head
design. In each case, the driving line
is electrostatically shielded. On the
circular model, the bucking -loop adjustment
handle is visible. The linear
model has the equivalent of a
fixed bucking loop, and a vernier
adjustment is provided remotely. An
0 -ring seals the linear head to the
test surface so that atmospheric
pressure may be used to hold it
firmly in position. The valve and
vacuum connection may be noted
extending parallel to the signal lines.
Dimensions are chosen on the
bases of area to be scanned, and of
maximum frequency. The models
shown have active diameter and
length respectively of 0.75 in., and
perform well from audio frequencies
to 100 Mc. Upper frequency limits
occur where the loop dimensions approach
a quarter wave length.
Copper -Clad Steel
Fig. 2 shows some prepared surfaces
of copper -clad steel, 0.050 in.
OFHC copper on ASTM -A -212 steel
0.450 in. thick. Initial testing showed
the stock surface 1.4 times the standard
loss. Machining operations, evident
in the upper set of samples,
were carried out in 0.001 in. steps.
All the samples with 0.003 in. or
more stock removal show conductivity
within a few percent of the
AUTOMATIC
Tape Scheduled
TESTING with
the New LAVO I E
ÌR000T[STEIt
ELECTRONIC
EQUIPMENT
SETS UP ENTIRE TEST
WITHIN HALF A SECOND
Actuated by a simple punched paper tape, the
Robotester eliminates the cost and bulk of
special program boards, "black boxes" and
sample units... does away with tedious hours
of preparation. Tapes are easily duplicated or
punched on the job for multiple and remote
testing. Compact, light weight.
SPECIFICATIONS
Measurement: DC resistance.
Range: 0 to 10,000,000 ohms in 1 ohm steps
or ir 1 %, whichever is greater. Internal
standard resistors are ± 1 %.
Tolerance: 5%, 10%, 20% with limits of
either"srnaller than," ±, or "greater than"
selected internal standard. Will reject all resistance
values outside standard tolerances.
Any of the three tolerance values and three
limits may be selected on the tape for any
external measurement, and successive tape -
programmed measurements need not have
the some tolerances. (May be "mixed" in a
series of measurements.)
Number of measurements: Between any
two of 240 points, or over 57,000 possible
measurements per set -up.
Speed: Approximately 120 measurements
per minute.
Dimensions: 20" wide x 131/4" high x 18"
deep (overall).
Weight: 90 pounds
I/vol¢ krw,r i%¢ernc.
MORGANV!t.LE 5,
NEW JERSEY
REPRESENTATIVES
ALBANY, J. A. Reagan Co., Albany 8 -5155 - ATLANTA,
Southeastern Industrial Instruments, Exchange 7801 -
BALTIMORE, Thomas L. Taylor, Belmont 5.9126 -
CHICAGO, R. Edward Stemm, EStebrook 9-2700-DEN-
VER, Allen I. Williams Co., Main 3.0343- EUCLID, O.,
Electro Sales Associates, Redwood 2-7444 - FORT
WORTH, Mitchell Speairs Co., Walnut 3- 8811 -HART-
FORD, M. S. Caldwell, Jackson 2- 5832 -LOS ANGELES,
T. Louis Snitzer, Webster 8-2074-MONTCLAIR, N. J.,
Louis A. Garten & Associates, Pilgrim 6-2900 - SAN
MATEO, R. L. Pfleiger Co., Fireside 5-1134-SEATTLE,
Testco, Mohawk 4895 -ST. LOUIS, Edwin H. Murty,
Jefferson 1-2075; Foreign: Ottawa, CAN., Computing
Devices of Canada, Ltd., Parkway 8 -1761. N. Y., Frazar
& Hansen, Ltd., WOrth 4 -3454, also SAN FRANCISCO,
Exbrook 2-5112.
360
For product information, use inquiry card on pages 209 -210
Tele -Tech & ELECTRONIC INDUSTRIES June 1956