Manufacturers
- California Instruments
- Camco
- Candy
- Canon
- Canton
- Carl Zeiss
- Casio
- CBS Laboratories
- Central Electronics
- Century Electronics
- Chauvin Arnoux
- Chicago Transformer
- Chinaglia Dino Elettrocostruzioni
- Chongqing XieGu Technology Co.
- Christian Schwaiger Gmbh
- Chrysler
- Citizen
- Clamann & Grahnert
- Claricon
- Clarion
- Clark Hess Communication Research Corp
- Clarostat Mfg. Co. Inc.
- Clatronic
- CM Clemens Manufacturing Company
- Coby
- Codar Radio Company
- Cognitive Vision Inc
- COHU Electronics inc
- Collins Telecommunications
- Combinova
- Commodore
- Communication Technology Group
- Compaq Computer Corporation
- Compliance Design Inc.
- Compliance West
- Conar Coletronics Service Inc.
- Cornell Dubilier Electronics
- Cosmed
- Cossor
- Coutant Electronics
- Cox
- Creative
- Crest Audio
- Crosby Laboratories
- Crown
- CRT
- Crumar
- CT Systems INC
- CTC Union Technologies
- CTX
- Cushcraft Corporation
- Cushman Electronics Inc.