Resistors: Color code training for electronics technicians and repairers

Andreas Thaler

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Anyone who deals with older electronic devices and cameras (e.g. Canon AE-1) will find wired resistors with colored rings. These rings give the resistance value, the tolerance and, if necessary, the temperature coefficient.

Those who are experienced can read the codes directly, everyone else uses tables or apps.

The TU Berlin offers a nice online training tool free of charge for reading the color codes:


The language is German but I think dealing with it comes naturally. Simply select the level of difficulty, enter the value read of the shown resistor and you will receive feedback whether it is correct or incorrect.

Ideal for the time between projects to stay fit

The color codes should be internationally valid.

Electronic color code - Wikipedia

en.wikipedia.org
 
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Chan Tran

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If a resistor is in good condition simply measure it would be easy. If the resistor is damaged mostly due to overheating the color may be very difficult to make out.
 

Alan Edward Klein

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When I was in the USAF in the 1960 learning electronics, we learned this to remember the color code number equivalents.

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There was a dirty one as well, but I don't think it's appropriate to post here

Numerically the value (0-9) of a resistor via the color-coded bands:
Black (0), Brown (1), Red (2), Orange (3), Yellow (4), Green (5), Blue (6), Violet (purple, 7), Gray (8), and White (9)
 

Alan Edward Klein

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Andreas Thaler said:
You've seen all those sleek silver jets and their test pilots?
Click to expand...

Nah. I was never on a USAF plane except on Armed Forces Day like the rest of the tourists.
 
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Andreas Thaler

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Alan Edward Klein said:
Nah. I was never on a USAF plane except on Armed Forces Day like the rest of the tourists.
Click to expand...

But as an electronics engineer, you maybe had cockpits as a topic, with their analogue displays and electromechanical controls?

The cockpit of the McDonnell Douglas F-4 Phantom II, flown by Lt. Col. Ron "Elvis" King of the 82nd Aerial Target Squadron Detachment 1, when he led the final military flight of the storied aircraft at Holloman AFB, N.M., Dec. 21, 2016. The F-4 Phant

Download this stock image: The cockpit of the McDonnell Douglas F-4 Phantom II, flown by Lt. Col. Ron Elvis King of the 82nd Aerial Target Squadron Detachment 1, when he led the final military flight of the storied aircraft at Holloman AFB, N.M., Dec. 21, 2016. The F-4 Phantom II entered the...
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koraks

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bernard_L said:
If in situ (soldered in a circuit) a real measurement is not possible.
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Yeah, although it depends on the circuit. Without knowledge of the particular circuit, a measurement can indeed not be trusted to determine the value. It'll still say something, but that's another story.
 

Sirius Glass

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Alan Edward Klein said:
I just remembered tolerances. gold= 5%; silver=10%; and nothing I think was 20%
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Gold 1%
Silver 5%
Nothing 10% or as we said a Hughes Aircraft, "Good enough for Government work."
 

Sirius Glass

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Alan Edward Klein said:
Interestingly, the USAF tested you for color blindness before entering and wouldn't allow you to be in electronics if you were.
Click to expand...
I used to assemble video systems for editing, broadcast, etc. A new guy started and I was checking his work and found everything miswired. Which was strange because he was in school as an engineer and was a smart guy. Turns out he was colorblind! We made him a board with samples of every cable, splayed out with text labels for each color wire. With this, everything went smooth. I think that there are different types of colorblindness but his at least meant that if you told him a particular color was, say, red, everything got wired up fine.
 
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Andreas Thaler

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Touching
 

Truzi

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I learned the "dirty" one in a high school electronics class


Sirius Glass said:
..., "Good enough for Government work."
Click to expand...
A coworker told me that phrase was once considered high praise, as Government specs were precise.
 

chuckroast

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Truzi said:
I learned the "dirty" one in a high school electronics class
Click to expand...

I learned the inappropriate one first as well There are many other, more
sanitized ones here - we can't have people getting triggered and sobbing in the corner:


List of electronic color code mnemonics - Wikipedia

en.wikipedia.org

Truzi said:
A coworker told me that phrase was once considered high praise, as Government specs were precise.
Click to expand...

Yabut govt spec also was way OVER specified. I heard this story years ago ...

In the early days of integrated circuits, the govt specified that certain chips should be ceramic encapsulated so that they could be sent to space and be more protected against cosmic radiation (in theory, anyway).

The chips exhibited an unusually high failure rate. When disassembled, it was discovered that the little gold wires between the actual chip and the external pins of the package were breaking. Why? Because the thermal coefficient of expansion/contraction for the external packaging was significantly different than the wires which broke when the chip exterior expanded sufficiently.
 
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Andreas Thaler

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Has anyone an idea where to find information regarding cockpit electronics of those days?

Countless discrete electronic components and cables must be installed behind the instruments.

Fascinating!

Were there computers in fighter planes in the 1960s?
 

chuckroast

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There were certainly some version of computers on aircraft carriers and early versions of fighter target acquisition systems of the day. They may have be analog or hybrid, I don't know. The big contractors of the era were companies like Ratheon, Hughes Aerospace, Fairchild, Boeing, McDonald Douglas and the like. Certainly, by 1968, computers built out of discrete chips were in use. See:

 

Alan Edward Klein

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I was a cryptographic technician. Never got out of the communications center.
 

Alan Edward Klein

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koraks said:
Yeah, although it depends on the circuit. Without knowledge of the particular circuit, a measurement can indeed not be trusted to determine the value. It'll still say something, but that's another story.
Click to expand...

We used to unsolder one lead and then take a measurement.
 

Alan Edward Klein

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Sirius Glass said:
Gold 1%
Silver 5%
Nothing 10% or as we said a Hughes Aircraft, "Good enough for Government work."
Click to expand...

I may be wrong, but back when I was doing these, it was 20%. This chart infirns the 5% and 10% for gold and silver but it seems to depend on the resistor type.

Decoding the Color Bands on Resistors: A Comprehensive Guide

Anyone working with circuit boards needs to know how to read resistors’ resistance values to prevent errors such as burned-out LEDs or microprocessor overheating. Today, color codes on resistors follow the international standard in IEC 60062, but that wasn’t always the case. In the 1920s and...
partstack.com
 
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