Electronics-World-1959-05

www.americanradiohistory.com
a quarter - century of PRECISION know -how
is now yours in
FOR:
electronic hobbyists
and amateur radio
hi -fi custom building
and service
science education and
technical schools
industrial testing and
quality control
P A
o
quality electronic equipment in KIT FORM
PACO is the only line of
test instrument kits engineered
and produced
under the auspices of a
leading test equipment
and meter manufacturer.
and, you pay nothing
extra for the convenience
of buying PACO kits directly
from your own
local parts distributor.
COMPARE PACO against
any other kits for performance,
appearance,
ruggedness, ease of operation
and simplicity of
assembly and wiring.
COMPARE PACO's superbly
detailed, step -bystep
instruction manuals
and giant size wiring diagrams,
against any you
have ever seen.
SEE HOW PACO sets an
entirely new standard in
electronic instrument kit
design and kit assembly
instruction.
IA
I r
Available and on display
at leading
electronic parts distributors.
Write low free
descriptive bulletin.
e -my-
4111
MODEL B -10
Battery Eliminator Kit
less than 0.3% ripple output
no external filters required
Kit Net Price: $41.95
Wired: $49.50
rTi 9
MODEL C -20
Res -Cap -Ratio Bridge Kit
10 mmfd to 2000 mfd
V2 ohm to 200 megs
Kit Net Price: $20.95
Factory Wired: $31.50
:
MODEL G -30
RF Signal Generator Kit
160 Kc to 240 Mc in 8 bands
120 Mc fundamental output
Kit Net Price: $29.50
Factory Wired: $39.95
-
MODEL M-40
High Sensitivity V -O -M Kit
20,000 ohms /volt DC
10,000 ohms /volt AC
Kit Net Price: $31.50
Factory Wired: $37.50
n
:
e
MODEL S -50
5" Cathode Ray Oscilloscope
push -pull vertical and
horizontal amplifiers
Kit Net Price:
Factory Wired:
P A
Kit
$49.50
$84.50
MODEL S -55
Wideband 5" Oscilloscope
response DC to 5 Mc
push -pull V and H amplifiers
Kit Net Price: $87.50
Factory Wired: $139.50
s
,*!r9I f-
a-
MODEL T -60
Tube Checker Kit
full free -point lever
selector system
built -in roll chart
Kit Net Price: $38.75
Factory Wired: $54.50
0 i
MODEL T -65
Transistor and Crystal Diode
Tester Kit
testsIcoo,gain, leakage, etc.
tests both p -n -p and n- p n types
Kit Net Price: $39.95
Factory Wired:
A'
MODEL V.70
Vacuum Tube Voltmeter Kit
wide -range
peak -to -peak
Kit Net Price: $31.50
Factory Wired: y47.50
6 .ï
1
1
MODEL Z-80
RF -AF Signal Tracer Kit
high gain RF and AF amplifier
visual and audible indicator
Kit Net Price: $29.50
Factory Wired: $42.50
ELECTRONICS
CO., INC.
70-31 84th Street, Glendale 27, L. I., New York
Export: 458 B'way, N .Y. 13, U.S.A., Canada: Atlas Radio Corp.. Toronto 19.
-`A DIVISION OF PRF, (I.S'IO.i APPARATUS COMPANY, INC.
will not be sufficient to decompose the
"Freon" during the test procedure.
This is quite different from the instance
of the halide torch where the
refrigerant gas is actually passed
through the torch flame. In radio and
TV service operations, the hottest condition
in the area would probably be
the hot tip on a soldering iron. In my
opinion, the normal precautions taken
during any soldering operation, where
ventilation is available is adequate to
take care of any conceivable use of
"Spra -Koat Circuit Cooler" in the
electronic servicing area.
You have raised the question of
smoking in the presence of "Freon."
This is certainly not advisable, but I
would not associate the intermittent
spray of "Freon" on a TV part for spot
cooling as a condition which should
prohibit smoking in the area. As a
matter of fact, here again if concentration
of "Freon" is such that smoking
causes decomposition, the smoker experiences
a very strong. unpleasant
taste sensation which, long before it
becomes harmful, will make him stop
smoking. You mention horseplay in
your letter. Of course. any horseplay is
dangerous and unwise. Liquid "Freon"
sprayed on the skin over a period of
seconds could result in frostbite.
A. H. LAWRENCE, JR., Manager
Aerosol Propellent Sales
E. I. Du Pont de Nemours & Co.,
Inc.
Wilmington. Delaware
TRANSISTORIZED TACHOMETER
To the Editors:
I have constructed the "'Transistorized
Tachometer" described in your
January issue exactly as suggested, except
that I used a 1N1508 International
MZ 43 zener diode in place of the
one suggested.
After placing the unit in service.
however, I observed the meter deflection
varied up to about 40 per -cent as
the temperature increased from about
20 °F to 75 °F. I would appreciate any
suggestions you might have on eliminating
the temperature effect.
SIDNEY ARNOW
Brooklyn, New York
Some of our readers hare had difficulty
in obtaining a source of supply
for the zener diode mentioned in the
article. Although the diode originally
specified is listed in Allied Radio's
latest semiconductor directory of instock
items, we have learned that
there is some lag in the delivery of
these units from the manufacturer.
We hope this situation is temporary
and that the diode will be more readily
available soon. Meantime, substitutions
such as the one suggested above
might be tried. Regarding Reader
Arnow :s temperature problems. here
is tvhat the author says.-Editors.
Dear Mr. Arnow:
The original experimental work on
the tachometer was done in New England
in late winter. Therefore, the
temperature problems were not en-
16 ELECTRONICS WORLD