CERAMIC DIELECTRIC TRIMMER CAPACITORS SG-305J
SPECIFICATION NOTES APPLICATION NOTES
Soldering and Cleaning
1. Parts are 100% tested for capacitance range,
of Ceramic Trimmer Capacitors
dielectric withstanding voltage, insulation resis-
tance, and torque.
Soldering temperatures and times are specified in
Notes 3 and 4 above. If using an iron for manual sol-
2. Capacitance range specified is that which is guar-
dering (for prototyping or repairs, for example) use
anteed, and is measured at 1 MHz and 25C.
an appropriate size and temperature so that the
3. For soldering SURFTRIM surface mounting models,
high temperature exposure of the trimmer is less
pre-heat at 140C 10C for 2 minutes maximum,
than 3 seconds.
and reflow solder at 240C 5C for 20 seconds
We strongly recommend the use of water soluble
maximum.
fluxes for soldering, followed by cleaning in water
4. For soldering printed circuit board mounting mod-
containing detergents, and then a clear water
els, solder at 260C 10C for 5 seconds maximum,
rinse.
except 3 seconds maximum for Miniature Models
Some operations still use Freon or similar fluorinated
(page 10).
or chlorinated hydrocarbon solvents. These solvents
5. Q factor is measured at maximum rated capaci-
have a tendency to remove the lubricant, which in
tance and at room temperature. Frequency of
turn makes for bumpy adjustment, and will degrade
measurement is as listed for each model.
the tuning torque, adjustment life, and other
mechanical specifications.
6. Dielectric strength is measured at maximum rated
capacitance and room temperature, with test volt-
In general, the minimum exposure to cleaning solu-
age as listed for each model applied for 5 seconds.
tions is recommended. The gentlest would be the
detergent and water rinses at fairly low tempera-
7. Insulation resistance is measured at maximum rated
tures. When chlorinated or fluorinated hydrocarbons
capacitance and room temperature and at rated
are used, the boards should never be plunged into
voltage, unless otherwise specified.
the solvent solution, but rather maintained in the
8. Temperature coefficient of capacitance (TCC) is
vapor area of the defluxing equipment, and for the
measured at 100 kHz or 1 MHz, over a temperature
minimum possible time. Most desirable would be to
range of 20C to +70C with capacitor set at maxi-
clean only the bottom of the printed circuit board,
mum rated capacitance.
as with board scrubbers.
9. Axial load during tuning should not exceed 250
The unsealed GKG models are usually specified for
grams.
consumer applications where cleaning after soldering
10. Capacitors should not be operated outside of is normally not required. Should cleaning be required,
rated capacitance range and working voltage. the method to use would be to clean the bottom of
the board, as with board scrubbers. If a solvent is used
11. Angular orientation of adjusting slot is random.
when cleaning the GKG series, sealed versions should
be specified to prevent the solvent from being
trapped in the housing and degrading performance.
Other precautions for using ceramic trimmer capaci-
tors include:
Beware of excessive handling with bare hands
as, finger oil and dirt can bring down Q and
insulation resistance values.
Terminals should not be cut or reformed, as this
could cause deformation of the spring or break-
ing of the rotor.
Sprague-Goodman Electronics, Inc.
1700 SHAMES DRIVE, WESTBURY, NY 11590
TEL: 516-334-8700 FAX: 516-334-8771
E-MAIL: info@spraguegoodman.com
WEBSITE: ENGINEERING BULLETIN
Sprague-Goodman
SG-305J
Supercedes SG-305H
CERAMIC DIELECTRIC
TRIMMER CAPACITORS
Sprague-Goodman Electronics, Inc.
1700 SHAMES DRIVE, WESTBURY, NY 11590
TEL: 516-334-8700 FAX: 516-334-8771
E-MAIL: info@spraguegoodman.com