Sangamo Capacitor Cross-Reference Guide
Sangamo Electric merged with Cornell Dubilier to form SangamoCDE, which was eventually absorbed entirely into Cornell Dubilier (now Knowles CDE). Sangamo-branded capacitors — silver mica (CM, CY, CDV, CD), hermetic dipped mica, and oil-filled power capacitors (Type AB, DA, GB) — are no longer produced new. Modern equivalents are available from CDE, Vishay, KEMET, and specialty mil-spec houses.
Sangamo Electric: A Brief History
Sangamo Electric Company was founded in 1899 in Springfield, Illinois as a manufacturer of electric meters. Through the 20th century the company expanded into capacitors, electronic instruments, time-switching equipment, and power-factor correction gear, becoming a major supplier to the U.S. military, the FCC-regulated broadcast industry, and the electric utility sector.
Sangamo’s capacitor reputation rested on three pillars: silver mica (the CM, CY, and CD types — prized for stability and low loss in RF tuned circuits and precision oscillators), hermetic dipped mica for military and high- reliability service (CDV mil-spec), and oil-filled paper power capacitors for utility power factor correction, industrial filtering, and high-voltage pulse applications.
Through corporate consolidation, Sangamo’s capacitor division merged with Cornell Dubilier to form SangamoCDE, and that joint entity was eventually fully integrated into Cornell Dubilier Electronics. Today, Cornell Dubilier (Knowles CDE) holds the institutional knowledge of the Sangamo product lines, and most Sangamo part numbers cross-reference directly to a CDE silver mica or film equivalent.
Demand for Sangamo replacements is concentrated in three areas: amateur radio and vintage broadcast restoration (silver mica), military and aerospace equipment sustainment (CDV hermetic mica, QPL-listed parts), and industrial maintenance for utility-class power factor correction installed before the 1990s.
Sangamo Mica Capacitor Cross-Reference
Mica capacitors do not degrade in storage and have effectively unlimited shelf life, so cross-references are direct: match capacitance (pF / µF), voltage, and tolerance. For mil-spec applications, also confirm temperature coefficient and QPL listing.
| Original Part # | Type | Capacitance | Voltage | Modern Equivalent | Notes |
|---|---|---|---|---|---|
| CM-15 / CM-20 / CM-30 | Molded silver mica | 1 pF – 0.01 µF | 100 – 500 VDC | Cornell Dubilier CD15 / CD19 / CD30 silver mica, Vishay CD-series | RF tuned circuits, oscillators |
| CY-10 / CY-20 | Hermetic dipped mica | 1 pF – 0.01 µF (typical) | 300 – 500 VDC | Cornell Dubilier CDV-style, Vishay hermetic mica | Mil/aerospace, hi-rel comms |
| CDV-16 / CDV-18 / CDV-19 | Mil-spec dipped mica (hermetic) | 5 pF – 0.05 µF | 300 – 500 VDC | KEMET CDV equivalents, Cornell Dubilier CDV-style | Military / QPL applications |
| CD-series (legacy) | Standard silver mica | 1 pF – 0.01 µF | 100 – 500 VDC | CDE CD15 / CD19 / CD30 (current production) | General precision RF |
| Type 5R / 6R | Postage-stamp mica (vintage) | 10 pF – 0.005 µF | 300 – 1000 VDC | CDE silver mica, Vishay CD-series | Pre-1960 radio sets |
| Type 30 button mica | Button-style hermetic mica | 5 pF – 1000 pF | 300 – 5000 VDC | CDE hermetic mica, custom-spec replacement | Vintage RF coupling, transmitters |
Sangamo CM-XX / CY-XX / CDV-XX type designators follow the EIA / mil-spec mica capacitor coding scheme. The number after the prefix indicates case size (e.g., CM-15 is the smallest molded case, CM-30 is mid-size). Capacitance and tolerance are coded into the body markings — older Sangamo capacitors used the EIA color-dot system (six-dot or nine-dot).
Sangamo Oil-Filled & Power Capacitor Cross-Reference
Oil-filled power capacitors are typically specified by capacitance, AC/DC voltage, and kVAR rating (for PFC). Modern replacements use metallized polypropylene rather than paper-oil dielectric — electrically equivalent for most filter and motor-run applications, with longer service life.
| Original Part # | Type | Capacitance | Voltage | Modern Equivalent | Notes |
|---|---|---|---|---|---|
| Sangamo Type AB / DA | Oil-filled paper power | 0.1 – 50 µF (typical) | 400 – 4000 VAC / VDC | CDE 942C metallized PP, Vishay MKP385, TDK EPCOS MKK | Industrial filter, motor run, PFC |
| Sangamo Type GB / SB | Oil-filled HV pulse / discharge | 0.1 – 100 µF (typical) | 1000 – 15000 VDC | General Atomics pulse cap, CDE 940C, Vishay HV film | Pulse modulators, energy discharge |
| Sangamo PFC bank | Oil-filled power factor | Multi-kVAR | 240 – 600 VAC (typical) | TDK EPCOS PhaseCap, ABB CLMD, Vishay PhMKP | Industrial PFC — verify kVAR sizing |
| SangamoCDE post-merger | Computer-grade screw terminal | 1500 – 33,000 µF | 10 – 450 V | CDE 381LR / 520C (direct in-family successor) | Industrial drives, UPS — produced under CDE today |
Sangamo oil-filled type designators (AB, DA, GB, SB) varied across catalog editions and military contracts. Confirm the exact capacitance, AC/DC voltage class, and physical envelope from the original case markings before substituting; some pre-1979 units may contain PCB-based dielectric fluid and require regulated disposal — see EPA guidance for legacy oil-filled capacitor handling.
How to Identify a Sangamo Capacitor
Sangamo capacitors used different markings depending on era and product family. The best identifying feature is the Sangamo name in script or block lettering on the body or case, often paired with the Springfield, Illinois address.
- Silver mica (CM / CY / CD) — Small rectangular molded plastic body, typically brown, beige, or black. Two axial leads. Pre-1960 production used the EIA six-dot or nine-dot color codefor capacitance, tolerance, and voltage; later production printed values directly. The Sangamo logo is a script “Sangamo” with a horizontal underline.
- Hermetic dipped mica (CDV / CY) — Slightly larger molded body with a glass-to-metal hermetic seal, often olive drab or military gray finish. CDV mil-spec parts carry the JAN designation (e.g.,
JAN CDV-19EF103J) — the prefix decodes to capacitance, voltage, tolerance, and temperature coefficient per MIL-PRF-39001. - Postage-stamp mica (Type 5R, 6R, 30 button) — Pre-1960 vintage, rectangular cardboard or molded body about the size of a postage stamp. Color codes follow the EIA standard. Often marked with a date code in YYWW or YYM format.
- Oil-filled power (Type AB, DA, GB) — Rectangular or cylindrical metal can with porcelain or rubber bushings on top. The Sangamo logo, capacitance, and voltage are stamped or printed on a silver or white nameplate. Date codes are typically a 4-digit YYWW or month-year format.
- SangamoCDE-era — Late-production capacitors marked with both names in transition; these are essentially CDE parts and follow the CDE part-number schema (see our CDE cross-reference).
For pre-1960 Sangamo mica capacitors with EIA color-dot codes only, the dot pattern decodes capacitance in pF (first three dots), tolerance, and rated voltage. Multiple capacitor coding charts exist online and in vintage RCA / Sams reference manuals.
What Replaced Sangamo?
The Sangamo capacitor business merged with Cornell Dubilier and is now fully part of the CDE catalog. Other Sangamo legacy product lines are best served by a small group of specialty manufacturers:
- Silver mica (CM, CY, CD) — Cornell Dubilier CD15 / CD19 / CD30 series silver mica are the direct in-family successors; Vishay CD-series mica is the primary alternative.
- Hermetic dipped mica / CDV mil-spec — KEMET produces a CDV-style hermetic mica line that matches mil-spec qualification for legacy applications. Cornell Dubilier also produces hermetic mica to specification on request.
- Oil-filled paper power (Type AB, DA) — Modern metallized polypropylene replaces paper-oil construction in nearly all motor run, AC filter, and PFC applications. CDE 942C, Vishay MKP385, and TDK EPCOS MKK are direct engineering replacements.
- HV pulse / discharge (Type GB, SB) — General Atomics pulse capacitors and CDE 940C HV polypropylene cover modern pulse-modulator and energy- discharge applications. Verify peak current and dV/dt against the original spec.
- Industrial PFC banks — TDK EPCOS PhaseCap, ABB CLMD, and Vishay PhMKP banks. Direct part-for-part substitution is rare; most retrofits are sized fresh in kVAR against the load profile.
- SangamoCDE computer-grade — The post-merger SangamoCDE screw- terminal computer-grade electrolytics are essentially CDE parts; the CDE 381LR or 520C is the direct successor.