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Basic Robotic References

Tom Dickens: thomas.p.dickens@boeing.com

One of the best resources for the robot builder is a good set of references. I'm in the process of compiling a set of Basic Robotic References, including electronics and mechanics, which I have find on the web. One problem that I find quite often on the web is that great references move or otherwise disappear. To alleviate this, I have found references which permitted copying, and have made local copies of them. There are a few references which I simply point to when I was unsure about the permission to copy the material.

If you find additional web-sites which provide similar but additional references, please let me know and I will try to add them to the list.


Table of Contents: Local References

Table of Contents: Remote References


Resistor Color Codes

Resistor values are represented by color-codes. The first band on the left side of the resistor specifies a digital value ranging from 0 through 9. The second band indicates a digital value ranging from 0 through 9. The color of the band indicates the digit. The third band designates the power of 10 by which the two-digit number (according to the first two bands) is to be multiplied.

The fourth band indicates the tolerance of the resistor's value from the indicated (color Code) value. There may or may not be a fourth band. If there is no fourth band, then the resistor value may be as much as 20 percent greater than or less than the indicated value. A silver band indicates that the tolerance is plus or minus 10 percent. A gold band indicates that the tolerance is plus or minus 5 percent.

A fifth band may exist - this indicates the failure rate. The failure rate is expressed as a percentage of units expected to malfunction within 1,000 hours of operation at the maximum rated power-dissipation.

Color 1st & 2nd
Bands
3rd Band
Multiplier
Last Band
Tolerance
BLACK 0 1     --
BROWN 1 10     1%
RED 2 100     2%
ORANGE 3 1,000     3%
YELLOW 4 10,000     4%
GREEN 5 100,000     --
BLUE 6 1,000,000     --
VIOLET 7 10,000,000     --
GRAY 8 100,000,000     --
WHITE 9 -- --
GOLD -- 0.1     5%
SILVER -- 0.01     10%
No Color -- -- 20%

Calculate Resistor Values
from Color Codes

    

Resistance Value:

Adopted from the web-site of Danny Goodman (dannyg@dannyg.com).


Resistor Values for a Voltage Divider

A voltage divider is two resistors in series (R1 & R2), one end connected to a voltage source (V Plus), and the other end connected to ground (0 Volts). This produces a voltage (V-out) between the two resistors. This voltage will be a value between 0 and V Plus. This value is determined by the equation:

V-out = V Plus * R1 / (R1 + R2)

In the following Applet, set the values for V Plus, R1 and R2. The V-out value will be calculated for you, as well as the current running through the voltage divider. It should be noted that if you connect a load from V-out to ground, the resistance of the load will cause the effective value of R2 to drop, causing the V-out value to drop. For high-impedance loads connected to V-out you should see little change in the V-out level.


68HC11 Microcontroller Page Tom Dickens: thomas.p.dickens@boeing.com