Free Stuff - FREE Home school downloads from Kinetic Learning Center, Dallas, Jim McMillan, Creatative Electronics & Robotics classes

The most common use of the Color Code is on resistors: A resistor has three bands on one end that define it's value & usually a gold (5%) / silver (10%) tolerance band on the other end.

The first band         =      a # from 0 to 9
The second band   =       a # from 0 to 9
The third band       =      the # of zero's following the first two numbers.

Example A: if the third band is orange: orange = the #3, or three zeros (third band).
Three zeros imply 1000 (1000 or 1 Kilo = 1K).

Example B: If the three bands are red, green, orange
This gives us: (2,5,3 zeros = 2-5-000) = 25,000 ohms = 25K ohms

Remember to start counting with zero (not one). ie: Orange is the fourth word in the sentence but the number three (3)... Black (black=0) Bear (brown=1) Rarely (red=2) Outrun (orange=3).

REVIEW:

The color code is used to mark the values on electronics parts. It's especially helpful when bulding kits or repairing circuits. It's important to be able to select the right value!

Black B ears Rarely Outrun Young Grizzlies But Victomize Gray Wolves

The first two color bands represent a number - the 3rd color band is the # of 0's AFTER the first two numbers! These colors are used to define the parts value.

Note: the numbers run from 0 to 9 (starting with '0', not '1')

A Resistor has three color bands that give it's value.
           The first band band is ..... a # from 0 to 9
           The second band is ......... a # from 0 to 9
           The third band is ............. the # of zero's following the first two #'s

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(2) Soldering Review:
Basic Steps to Soldering Success.....

(1) To check if the iron is hot - hold your hand over it (heat
       rises). Keep the tip clean by wiping on a damp sponge.
(2) "Tin" the tip by applying a small amount of solder - look for
       a smoke signal. You may need to scrape the tip &/or dip it in
        'flux' ("smelly jelly") and re-tin it.
(3) Locate the 'Hot Spot' a shiny spot of melted solder on the irons tip.
      You must always use the hot-spot to transfer heat! If necessary,
    scrape the tip, dip in flux (smelly Jelly) & re-tin to get a hot spot!
(4) Equally heat both parts by applying the "hot spot" to the
      junction of the two parts. Pre-heat the joint then add a small
       amount of solder to the hot spot at the point of contact. Hold
     the Soldering Iron at a 45 to 60 degree angle.
(5) Remove the solder but always keep the Hot-spot on the connection
       until the solder "flows" - then remove the Iron.
(6) REVIEW: Apply HotSpot (heat), Apply solder - Remove solder
     (wait for solder to flow then) Remove the heat(soldering iron).
(7) Keep the parts still until the solder cools or "sets" (3 - 5 sec.)
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(8) If done correctly the joint should look smooth & shiny. If it looks
      dull/flaky, it's a cold solder joint, simply reheat to fix. Make sure
     the complete joint and/or pad are evenly covered with solder.
(9) Clip off the wire close to the board (but not so close you cut
       the etch) and then reheat the joint until the solder "flows" again - just to be sure it's
       a good joint.
(10) A good connection should leave the surface of the wire or pad
        evenly covered.
(11) The finished solder joint should look like a small shiny volcano
        shaped cone.
CAUTION: Do not overheat, that can remove the "etch" and also can
       destroy transistors & intergrated circuits.

Important Facts To Remember:

* Soldering iron tips get very hot & burn anything they touch.
* DO-NOT waste solder by "chasing" it on the tray or table.
* Always put the soldering iron in its holder (spring) when not in use.
* Always be careful not to burn the power cord.
* Keep the Tip clean by carefully wiping it with a sponge.
* Visually check for shorts (across the etch) or poor solder joints.
* Burns can be painful for days - use first aid cream if burned.
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(3) Electronics Fundamentals:

RESISTORS:
A device used to set voltage levels in a circuit. It's value is measured in ohms which are always positive numbers. We say that resistors have a "voltage drop" across them when power is applied. There value is given by a series of three bands/rings on one end. When building a circuit try to install them with the "bands/rings" to the left or top of the board. This makes it easier to trouble shoot, esp if testing a bunch of boards!
CAPACITORS: Are used to block DC, like a road with a bridge out/up stops traffic. However non-DC signals can hop across or pass through the capacitor. The signal will altered in size &/or shape as it passes through the capacitor.
An "electrolytic capacitor is a special type of capacitor that can store a charge (& hold it for up to 6 months). Capacitor values are usually very very small and are measured in "Farads". A micro farad is 1x10 to the minus 6th power (a millionth of a farad).
An electrolytic capacitor is usually round with a positive and a negative lead. The neg. lead will be marked by neg. signs (-) or arrows on the side of the case. In electronic parts when two leads come out of the same end then the long lead is positive.
DIODES: are used to control current flow and seperate circuits (regular diodes), set voltage levels (Zenor diodes), and to generate light (LED's). An "LED" is a light emitting diode. Diodes have number printed on them like 1N914 and a band/ring on the negative end. The symbol is an arrow with a vertical bar on the pointed end, The arrow is the anode (+ end) and the vertical bar is the neg (-) end. In a circuit current (I) flows from positive (+) to negative (-) or in the direction of the arrow (in symbol).
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Transistors: A transistor acts like a switch and is controled by input voltages or symbols. Transistors are used to shape signals and control circuits. Transistors have either a NPN or PNP junction which determines the voltages necessary to turn them on or off. There are many different types, uses, shapes and sizes. The most common is a DIP (dipped in plastic) which is a small black plastic case rounded on the back with a flat face. The type (ie: 2N3904) will be stamped on the face as will the manufactors name or symbol. A transistor has three leads: A Base, usually the center or middle lead, a Collector, and the Emitter. The symbol for a transistor will always have an arrow on the Emitter. If the arrow is pointing into the transistor it's a PNP, if it's pointing out it's a NPN.
Switches: A switch is simply an on-off mechanical device whereas a transistor is an on-off electronic device. The most common examples are:
(SPST) Single Pole Single Single Throw. One input pole & one output
(SPDT) Single Pole Double Throw. 1 input, 2 output positons
(DPDT) Double Pole Double Throw. This is essentially two SPDT switches
             "ganged" together - if you throw one you throw both...
(Mom) Momentary contact switch. Usually a SPDT switch. A Momentary switch is
            usually normally open (NO)- when you press on the switch it will close
            while you hold it down. A SPDT Mom switch has two positions; NO and
            NC (normally closed). You can wire it to opperate in either mode.
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(4) Power Tool Introduction :

(1) Power Sanders:
I recommend using a combination 1" belt sander with a 5" disc. Under age 9 should use only the 1" belt sander! This tool is very safe - main danger is filing your fingers/finger nails. When using the 5" disc try to keep your work piece on the side of center (of the disc) that rotates into the table, the other side can throw objects up & in your face due to the direction of rotation of the disc. ALWAYS wear safety goggles and keep a firm grip on your work piece when using this tool.

(2) Drill Press:
Again a very safe tool if used correctly. Put a piece of wood on top of the table to drill into, align Drill bit so that it'll go into hole in the table - not the table itself. Hold down firmly on your work piece or use a bench vise or clamps. Be especially careful drilling metals and plastics - they can "grab" your work and spin it in the air! If this happens DO NOT try to grab it, either turn off the power switch or unplug the tool. ALWAYS wear safety goggles and keep a firm grip on your work piece when using this tool.
(3) Band Saw: The most dangerous of the tools covered here! Always think of the fact that this tool can cut your finger off! Not to 'FEAR' but to have a 'Healthy Respect' for the tool! Do not wear long sleeves or coats when using this tool. Let the material dictate the speed - slow for hard materials, faster for soft woods, etc. Never put your fingers in a position where if you slipped they could go into the blade. Try to keep your fingers at least 1" from the blade and never 'Force' the work piece. Try to never have to 'back-out' the blade, if you do be very careful and follow the contour of the cut or you'll pull-off or break the blade. Always take your time when using this tool. When about to cut through your material push with the hand holding the bigger piece and guide with the other hand - gently push through at the end of the cut!

(4) Dremel Tool:
Or any small hand drill - guide the 'Bit' straight both going in & coming out, do not use to 'wallow-out' a hole (make it bigger). To much pressure on a smaller drill bit will break it, too fast a drill speed will burn it up!
Not Yet completed - but I am working on it!
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(5) Rules for Kit Building

(1) Open the kit and check to be sure that you have all the "right" parts.

(2) Keep all of the parts in a parts box. Do not leave them loose on the table. If you do, you will surely lose some key part (Murphy's Law).
Murphy's Law: Anything that could go wrong -probably will.

(3) Check over all the instructions, diagrams, pictures, drawings and written information. Everything you need will be there someplace but sometimes you have to look (or search) for it.

(4) Before you start to assemble the kit be sure you understand all of the steps. You, of course, must read them to see! If not sure of something ask someone before you start.

(5) There's a saying... An ounce of prevention is worth a pound of cure!
It's better to take a little time before starting & do it right than spend hours trying to correct (if you can) your mistakes.

(6) Follow instructions, step by step and check off each step as you do it. The order is sometimes important due to the size or positioning of the parts. If a resistor is to stand on its end check that you position it so that the bare wire side will not short to something close by.
Sometimes you may want to lay down a part instead of normal positioning so it will fit into the container (box) you plan to use!
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(7) Put the part in place, double check that it's the "right" part for that spot, then press in down on the board (leave transistors apx. 1/4th inch off the board) and solder one lead, check that it's on the board in proper position then solder the other lead/leads.

(8)When installing a part with long leads, place leads through the hole on the "component" side of the board and slightly bend outwards (on the "etch" side) to hold the part in place while soldering.

(9) Use good soldering technique (see soldering 101 guide), don't overheat or use too much solder - just enough to cover the wire &/or the pad. Cut off the leads close to the board and reheat the connection to insure a good solder joint.
Soldering is simply the most important part of Kit Building - next to putting the right part in the right hole (& facing in the right direction).

(10) Before applying power to the circuit throughly check and recheck every part & solder joint. Make sure the right parts are in the right holes and that transistors, diodes & capactors are not in backwards, etc...

(11) Use a test meter or buzzer to check for shorts between lines of etch and across power lines. Look for unsoldered or bad soldering joints.

(12) Make sure no wires, leads or components are positioned so they could cause or become a short. Make your work look as neat as possible.
Whenever you complete a task, ask yourself - Is this as good as I can do?
If the answer is YES! then great job (no mater what anyone else thinks).

IF the answer is NO - then ask yourself, Why Not!
Always try to do your best - then you will be happy with what you do.
May God Bless the work of your hands!
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Tips For Kit
Building Success!
This section is currently being updated

1)   Put electrolytic capacitors down flat against the board to protect the etch.
2)   You must put the parts in correctly - check polarity & alignment.
3) Follow directions, most mistakes result from not paying attention to details.
4)   Always double check your work - before soldering in the part!
5)   If not sure ask for help, it can save hours of time and/or the project.

6)    Helpful Hints On Using Tools:
Soldering iron - use to solder, remove solder and to strip wire. You must have a sharp tip, hold it against the part then add solder.
Wire cutters - to cut small wire, not paper, plastic, coins or
metal objects. Use tip to snip leads at solder joint, main blade for heaver stuff.
Long nose pliers - use to hold hot stuff, bend wires around post, wrap/twist wires. Learn to open & close using one hand (if don't have a spring in pliers).
Screwdrivers - put handle in your palm & twist screwdriver with your fingers, keep pressure on the screw & hold SD vertical, don't let blade slip out of slot.
De-Solder Tool - When hot squeeze the Bulb several times to clear out any old solder (not over the PCB). Squeeze & hold the bulb, place on the solder joint until the solder melts then release bulb to 'suck' up the solder. Clear the bulb as before and do the other lead, do twice if necessary! You should be able to gently remove the part, do not force it in/out. Straighten & thoroughly clean the wire and the hole before re-installing use braid for maximum cleaning.
Solder Braid - apx 1/8th in. width, push it in to make it wider and to absorb more solder. Place braid over the joint and heat with soldering iron to 'wick' away solder. When saturated move up 1/4th in. or cut it off. Braid is expensive so don't waste it, leave it on the roll, cutting off chunks just adds waste!

7)    Soldering tricks - when installing a part,
� Put part in correctly & re-check to make sure it's right!
� When using polarity sensitive parts make sure positive wire goes into the + hole.
� Check orientation of Transistors. LED's, Diodes, Capacitors, etc...
� Check if part is positioned correctly (esp. IC's then solder one pin and
       check to see if part is against board before continuing.
� Note that E-caps (electrolytic capacitors), transformers & IC's have special
        position markings such as Dots, notches & negative stripes
� Sometimes it helps to use tape to hold a part in place while you solder.
� When soldering on a part notice how the surrounding etch lines run. Try to
         avoid bending leads towards another line of 'etch' and always solder
          away from an etch if possible - to deduce the risk of shorts.

8)    Parts Placement-
� Double check each part before you solder it in place, most major hard-to-fix
         problems occur because of soldering or replacing parts.
� In some cases a part is meant to stand on its end - if so there will be a circle
         with a hole in it (body of part) & another next to it for the other wire.
        ie: if a resister put its body down against the board in the circle with 3
         rings or bands up, put the other wire through the other hole!
� Remember long lead implies positive and the short lead negative!
� Most kits PCB's have drawings/symbols with the parts listed in or next to them.
� A resister will be R# (R1) and they usually give Part type/number, value, and the
         3 band colors. On the board will be a rectangle with part # in it.   R1...R4
        means R1=R2=R3=R4=are the same value (ie:10K).
� An elecrtolytic capacitor (E-cap) will have a positive sign in the PCB circle
        mext to the caps + wire hole. Circle size = physical size of Cap. Value of
       Cap is written on its side.
� On the board a Diode will have a rectangle with part # (ie: D1) and a line on the
         negative end. The line on a Diode (part/symbol) will always be on the neg end.
� An IC, integrated circuit, symbol will have a notch/dot on the pin one end.
� A line on a part indicates the negative end. On a diode the line in the symbol
         implies the negative (-) end. On an E-capacitor is a bar with one or two
         negative signs - this indicates the wire on that side is the negative lead.
         In an LED negative is indicated by line in symbol & flat side of case.
� Transistors - should be installed at least 1/8th inch off the board (thickness of a
         small paint stick) to prevent overheating when soldering. The T part number
         (ie: 2N3904) is written on the 'face' (flat surface) of the transistor. Be sure to
        install the trans. in right location with 'face' side matching drawing on PCB

9) Parts Removal - if you need to remove a part ...
� Locate the parts wires & pads circles on etch side of the PCB
� Use Solder Braid or De-solder tool (see learn to use tools, above)
� Be careful removing a part so you don't break it. Apply gentle pressure using an
         Exacto knife (ie: under a resister) or long nose pliers for bigger parts.
� Most serious problems come when putting parts back in (new/used) you must be
         careful not to lift, tear or crack the etch - be sure to clean parts.
� Do not force a part into a hole, it will rip the etch off the board.

If I missed anything, made a mistake or you have a suggestion then
e-mail me the information... Thanks Jim McMillan

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