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Resistor Codes
A Resistor is an electronic component that is deliberately designed to have a specific amount of resistance. Values range from less than 1 ohm to millions of ohms; power dissipation ratings are usually 1/4 watt or 1/2 watt. Some carbon resistors have power dissipation ratings of more than 1/2 watt or less than 1/4 watt. When a large amount of current must be handled, resulting in a power dissipation of several watts, wirewound resistors are used. On most carbon-composition resistors, it is not possible to print the value of in ohms, because the part is too small and because heat can cause printing to fade. A standard color code has been formed for us to use on the resistors. The color coding gives the value of the resistor in ohms, and tolerance above and below the indicated value.

The first and second bands on the left side of the resistor specify a digital value ranging from 0 through 9.

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 tolerance value may be as much as 20 percent greater than or less than the actual value indicated on the resistor.

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.

A resistor's weight indicates its power rating. Resistors with less than two watts power rating weigh less than an ounce, but high-power resistors are larger.

Ohm's Law
     E = IR
     I = E / R
     R = E / I
     P = I²R

Capacitor Codes
Large capacitors have the value printed plainly on them, such as 10.uF (Ten Micro Farads) but smaller disk types along with plastic film types often have just 2 or three numbers on them?

First, most will have three numbers, but sometimes there are just two numbers. These are read as Pico-Farads. An example: 47 printed on a small disk can be assumed to be 47 Pico-Farads (or 47 puff as some like to say)

Now, what about the three numbers? It is somewhat similar to the resistor code. The first two are the 1st and 2nd significant digits and the third is a multiplier code. Most of the time the last digit tells you how many zeros to write after the first two digits, but the standard (EIA standard RS-198) has a couple of curves that you probably will never see. But just to be complete here it is in a table.

Third digit: Multiplier (this times the first two digits gives you the value in Pico-Farads) 0 1 1 10 2 100 3 1,000 4 10,000 5 100,000 6 not used 7 not used 8 0.01 9 0.1

Now for an example: A capacitor marked 104 is 10 with 4 more zeros or 100,000pF which is otherwise referred to as a 0.1 uF capacitor.

Most kit builders don't need to go further, but I know you want to learn more. Anyway, just to confuse you some more there is sometimes a tolerance code given by a single letter. I don't know why there were picked in the order they are, except that it kind of follows the middle row of keys on a typewriter. So a 103J is a 10,000 pF with +/-5% tolerance

Letter Symbol Tolerance of Capacitor D +/- 0.5 pF F +/- 1% G +/- 2% H +/- 3% J +/- 5% K +/- 10% M +/- 20% P +100%, -0% Z +80%, -20%