The Sprague-Goodman parts are numbered by Dielectric, Form Factor, Cap Code, and Modifications. Take the example of GXA9R000, a plastic capacitor. The part number is divided into four important categories:

Dielectric:

The advantages and disadvantages of the various dielectrics are detailed above. Use the dropdown menus below to identify which part numbers signify which dielectrics.

Form Factor:

The form factor refers to the physical dimensions of the trimmer cap, as well as the placement of the adjusting screw (Top/Bottom or Side). If only a single digit is written then the capacitor has square dimensions. “8 mm” for example refers to “8x8 mm.”

Cap Code:

The cap code is a three digit number that identifies the capacitance of a capacitor. The first two digits are significant, and the third digit is the number of trailing zeroes. For example, 202 would be 2000 pF. An R indicates a decimal point, so 1R6 = 1.6 pF.

Modifications:

Various modifications that can for example, change the number or positioning of the leads. More information can be provided in the Sprague-Goodman catalogs.

Multiturn PTFE Dielectric Trimmer Capacitors

These capacitors combine the outstanding electrical properties of PTFE with nonferrous metal parts to provide high Q, high DWV, high IR, excellent conductivity, corrosion resistance, high resolution, and excellent stability. They are used on industrial and commercial grade equipment.

Filmtrim Plastic Dielectric Capacitors

These capacitors are used on industrial, commercial and consumer grade equipment. These include mobile radios, transmitters, pagers, instruments, electronic games, CATV, and wireless security and fire alarms. They come in a variety of capacitance ranges, sizes, and dielectrics. There are many modifications available, and the cost for commercial/industrial application is low.

Glass PISTONCAP Precision Trimmers

Glass capacitors give very high Q and stability, and they are very resistant to external pressures such as moisture and vibration. There are three dielectrics. The standard glass is least expensive and will suit most applications. If a greater Q or higher capacitance is required, then the more expensive high-range glass would be advisable. For applications involving moderate RF currents, fused quartz is used. Quartz trimmers are about three times more expensive than standard glass trimmers. There are many possible variations on the glass trimmers, with a choice between sealed or unsealed, and a possibility of an expanded range model. Used on military and professional grade equipment.

Microwave Sapphire PISTONCAP® Trimmer Capacitors

Sapphire trimmers have very high Q at UHF and microwave frequencies, and are extremely stable over temperature, frequency, voltage, etc. They are also very small, and they can be very precisely adjusted. However, these capacitors are also very expensive. They are used on military and professional grade equipment. They are frequently used in stable oscillators, frequency multipliers, filters, tuning cavities, and coupling.

Mica Dielectric Compression Trimmer Capacitors

Mica capacitors have high Q, large capacitance ranges, and very good RF current handling capability. They are used on industrial, commercial and consumer grade equipment carrying RF power and/or requiring high capacitance. There are many forms and mounting styles available. The part numbering system differs slightly from the other trimmer capacitors in that there are five categories, with the mounting styles and size identified separately.

Ceramic Dielectric Trimmers

These capacitors are used on industrial, commercial and consumer grade equipment. While they may not be as stable or efficient as some of the other dielectrics, they are very low cost and have a wide selection of capacitance ranges.