Radio Reference

Technical DataMany Circuit Diagrams and much valve (tube) information is available for British radio and television sets.
Crystal SetsAll about crystal sets with original images
Condenser Colour CodeThe British colour code for marking condensers as they were known in bygone times, capacitors as we know them now.
Resistor Colour CodeHow the early resistors were marked, body, tip and spot method.

Condenser (Capacitor) Colour Code, British.

Colour Number Tolerance Voltage Rating
Black 0 - -
Brown 1 1 100
Red 2 2 200
Orange 3 3 300
Yellow 4 4 400
Green 5 5 500
Blue 6 6 600
Violet 7 7 700
Grey 8 8 800
White 9 10 1000

The first three bands indicate the value in micro-micro farads, the fourth the tolerance and the fifth the voltage rating. The forth and fifth bands commonly omitted. If the colours are split in different sides the "group of three" will be the value.

Condensor Example Note: In todays' terms micro-micro would be pico Farads,pF (10-12) and condenser translates to capacitor!

In the example shown the value is , 300 mmf (pF), a tolerance of 5% and DC voltage rating of 100 V.

Resistor Colour Code

Colour Value
Black 0
Brown 1
Red 2
Orange 3
Yellow 4
Green 5
Blue 6
Violet 7
Grey 8
White 9
Gold Tolerance = 5%
Silver Tolerance = 20%

The body colour gives the first figure, the tip the second figure and the spot the number of "0"s that follow. Sometimes a fourth colour is added to the end opposite the tip to show the tolerance. Standard resistors not marked will have a tolerance of 10%.

Resistor Example In the example, Tip = Green, 5, Body = Red, 2 and Spot = Orange, 000 So the value is 25,000 Ohms.

Sometimes the spot is placed as a band rather than a circular spot.

Note: Today's band value followed this earlier method.

Trivia Quiz: What did Reginald Fessenden do before anyone else?

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