British 1940s components that are driving me dotty Small rod types with body/end/dot colours red/red/green orange/orange/green yellow/purple/yellow brown/black/brown
what meaning to the yellow and green multiplier dots ?
and Hunts make, brown cased small block, flat leads, with code oc/3100 impressed into the encapsulation none of them measuring anything like I think the colours/codes mean
In the back of Vol. 2 of the RSGB Radio Communication Handbook it shows two types of ceramic caps. The first has axial leads and the first color band is wider and is TC then 1st, 2nd, M, T. The other has radial leads and has a dot for the tip then 1st, 2nd, M, T.
I have seen some old small block caps just marcked with pF values.
Mike AA8W
two
has
TC = Temp coeff ? M,T = ?
These were body, end face (as leads are formed to loops around the ends) and dot, I will try and take a photo , when I get some time. One was broken and I removed it and replaced with an old axial but plate rather than tubular.
two
has
The broken one, a bit of the paint with the green spot , broken away. Body and end blob , both orange, presumably 33pF
-- Diverse Devices, Southampton, England electronic hints and repair briefs , schematics/manuals list on
This thread must have taken a turn that I missed. The device in the photo sure looks like a resistor !?!
-Bill
Sorry about that TC= Temp Coeff M=decimal multiplier, same as resistors to orange. Then gray = .01 and white = .1. T= tolaerance More than 10pF black = 20, red = 2, green = 5, white = 10. All + - %
Mike AA8W
My first thought on seeing that solid black core, expecting tubes if caps. But all of that size and format measured over 30M ohm, if resistors, and that broken one >500 Meg on an insulation tester. Also very small physical size , for the time, if they were resistors. Anyone interested in a microscope view of that core?, i could take such a pic, or any suggestions for chemistry test ?
-- Diverse Devices, Southampton, England electronic hints and repair briefs , schematics/manuals list on
Thats a new on for me. So what forms the two sides of the capacitor? Is there any sort of plating on the black core underneath the paint?
-Bill
caps.
physical
suggestions
The paint is laid directly on the black stuff. In a x30 microscope it has a slightly porous structure like scaled down clinker but not regular fine structure like ferrite slugs. Some ceramic type materials used in 1954 reference for capacitor construction were Clineonstatite, Magnesium Titanate, Rutile, Strontium Titanate, Barium Titanate, Barium-strontium titanate. But what any of them look like I've no idea.
-- Diverse Devices, Southampton, England electronic hints and repair briefs , schematics/manuals list on
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