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