I tend to casually use a range of technical terms and abbreviations in this site; which may seem like a bad habit, but then, it’s my notebook. This page is for clarifications, usually where a term gets used on multiple pages. Not everything is likely to be explained here, but if there’s something really inexplicable and not covered somewhere else, ask.

B-E-D or B-E-S

Body-End-Dot (or -Stripe)

A colour code method used on some cylindrical resistors and capacitors in the mid-20th Century. The body colour is the first significant figure, the end colour (the end with no tolerance stripe) is the second, and a dot or stripe of colour is the multiplier. Tolerance end colours were either gold, silver or none. The implementation may not have been consistent between manufacturers.

CCR

Carbon Composition Resistor

Carbon Composition is a sort of graphite paste which was (and still is for specialist purposes) used to make resistors. It attracts moisture over time if not kept warm, producing changes in resistance. Most ordinary CCRs seem to rise in resistance, eventually exceeding tolerance. This can to some extent be reversed by drying out in warm conditions, and restoration by recoating with a moisture barrier e.g. shellac. The paste can also be permanently damaged by excess heat, e.g. in soldering. CCRs tend to produce signal noise, so it may not be worth retaining them in old circuits; on the other hand they handle high voltages particularly well so are still used in some specialist equipment.

A variant is the Ceramic-Cased CCR (CCCCR), in which the paste is injected into a ceramic tube and capped off with resin at both ends. This is significantly more resistant to moisture ingress; they tend to remain in-tolerance for longer.

Some CCRs and CCCCRs were made using a stabilised paste; these frequently remain at or close to their original values after thirty or forty years; as good or better than Carbon-Film resistors of the same age.

Both types are found very widely in musical equipment from the 1960s and into the 1970s, particularly valve equipment.

Comment or Question about this page? write

Article text ©2022 Electropict .
Click images for individual licences.