Introduction: Electronics Building Tips ( in 21 Plus Steps )

By Me at one of my favorite web
About: For now see me at: http://www.opencircuits.com/User:Russ_hensel

I have been building circuits for a long time and may have picked up some ideas that may be new to more recent builders. There is nothing very hard or astonishing about the tips but they have helped me and may help you too.  In my mind a tip is not an electronics project ( but occasionally may involve putting together a mini-project ) or full directions on say "how to solder".  A tip is more a little trick in  technique or approach.  All of the following should fit this definition.

Step 1: Cardboard Parts Holder

When you are building, and particularly prototyping you tend to have a lot of parts, often ones that look alike, hanging around. Put them down and who knows what value they are.  Good old Heathkit ( RIP  http://en.wikipedia.org/wiki/Heathkit ) had a nice solution, insert the leads in corrugated cardboard and identify the part by writing on the cardboard.  Pictures will stand in for the next 1000 words I might otherwise write.

 

Step 2: Ignore the Resistor Code

You can get all sorts of calculators etc for decoding resistor color codes and values. I say throw them out.  Even if you know the codes it is easy to misinterpret the colors, and many resistors, like most 1% ones do not use the color code. Instead it is easy to measure them. Leave out a meter set on resistance and give each part a quick check before you use it.  Do this even if you have pre-sorted the resistors, it is easy to miss-sort.  The device in the picture helps.   You might want to build one of these and keep it on the bench while you are building:  Third Hand for Your Multimeter by russ_hensel  https://www.instructables.com/id/Third-Hand-for-Your-Multimeter/


The same thing pretty much true of small caps: use a capacitance meter.  

Step 3: Banana Plugs and Jacks

Banana plugs look a bit like a very small metal banana. They are very useful as they plug into a lot of things. Especially banana jacks ( see picture ). But you should also know they fit lots of other things. Most binding posts have a jack built in. ( see picture ).  My favorite banana plugs are called stackable banana plugs, they have a jack at the back, and you can plug one into another and stack them up see the pictures.  Pamona makes them, not sure what the best source is but here are a couple of links: 
 

and some similar ( and cheaper ) ones:

Banana plugs also fit some other things, one very handy thing is the standard alligator clip ( see picture )  Using the alligator clip is usually better if it wears its boot.

If the banana plug does not fit, perhaps you should adapt it, the pictures show how some tubing and banana jacks can be added to a test probe to make the probe jack-able.

Step 4: Make Adapters

The banana plug adapters are not the only ones you can make. Just one example: Make a jack for a meter probe. Mine is made from a bit of bare wire, wrapped to fit the probe and then soldered to the clip. I needed a little tape on the boot at the end.  ( see pictures )


A very fancy adapter I made for RS232 cables is:  Tea Connector for Serial RS232 Cables by russ_hensel  https://www.instructables.com/id/Tea-Connector-for-Serial-RS232-Cables/  

In fact adapters were an early theme of mine on instructables:


Sometimes it may even be useful to buy adapters ( see pictures ). 

 

Step 5: Look Up the Datasheets

If you are using a component go on the web and look up its datasheet ( use the part number and the keyword “datasheet” )  Not only will it give you the parameters of the part, but the pinout, and often, useful circuits.  Also use the keyword “application note” ( sometimes “app note” ) which may or may not exist for your part.  Typically they are loaded with useful circuits.  Oh and "rtfm": read them.

Step 6: Print Pinouts

When prototyping it is nice to know what pin on an IC is what. You can grab the pinout pictures from the data sheets ( for example the 555 from  http://www.ti.com/lit/ds/symlink/lm555.pdf   ) The pinout is usually the top view.  If you are working on perf board you really need a bottom view.  To get this just use your image editor ( I use paint shop pro ) to miror the picture.  These pictures can then be added to a document ( I use open office ) with both a top and bottom view or multiple parts.  You can annotate the document as you want. Print it out and hang it up over your prototyping area while you work.  

Step 7: Make Sure You Can See

Use lots of light, a swing arm desk lamp like this I have several in the lab. Since my work bench is just a sheet of plywood with some reinforcing around the edge, I make lots of extra mounts for the lamps by drill the appropriate size hole in edge. Now I can move the lamp to the best position easily.  ( interesting how many swing arm lamps there are see:  http://en.wikipedia.org/wiki/Balanced-arm_lamp  )
 

A head mounted magnifier keeps getting more useful as parts get smaller and your eyes get older. This cheap Harbor Freight one works for me. I like this better than a magnifier in my hand or even on an adjustable arm.  (  http://www.harborfreight.com/magnifier-head-strap-with-lights-38896.html  and one I like a bit better  <now gone it is the one in the picture> Not sure this is useful but "great look"  http://www.amazon.com/Watch-Repair-Magnifier-Loupe-Glasses/dp/B007YBEHIO/ref=sr_1_4?ie=UTF8&qid=1389025042&sr=8-4&keywords=magnifier+glasses  and finally the ones I think HF used to carry: http://www.amazon.com/Headband-Glasses-Magnifier-Reading-Antiques/dp/B004WRN5HM/ref=sr_1_2?ie=UTF8&qid=1389025042&sr=8-2&keywords=magnifier+glasses )

 


Step 8: Nut Starter

This is not really electronic, but often you need to assemble your project. Sometimes this involves starting a nut in a place that is really hard to reach. Heathkit had a solution, a nut starter. Basically this is a rod with a recess that just fits the nut. The recess should be somewhat elastic, plastic, rubber.... You place the nut into the recess, then you can reach way in and get the nut started. Not too hard to make, a different one for each size nut. You can even buy them. http://mendatools.descoindustries.com/MendaToolsCatalog/SpecialtyTools/35120/#.UrG--kD4tbI

Step 9: Coin Envelopes

Coin envelopes are small paper envelopes. Use them for small parts. Why? Because they are cheap , a couple of cents a piece, you can write on them, and they are stiff enough to line up in drawers of boxes. Check them out in the pictures. They come in various sizes. Get them at stores like Office Max or at Amazon perhaps http://www.amazon.com/Columbian-CO540-4x3-1-2-Inch-Envelopes/dp/B001IZF7GI/ref=sr_1_1?ie=UTF8&qid=1387420248&sr=8-1&keywords=Coin+Envelopes

 

Step 10: Strain Relief

Wires that will move or be pulled on after construction should have strain relief. This means that the wire will not pull on its electrical collection. There are many ways to do this, grommets, clamps, hot glue. On a perfboard you can weave the wire through and extra hole.  

 

Step 11: Color Coded

When wiring use different colored wires.  This makes keeping track of the wiring much easier.  Salvaging wire from cat 5 cable gives 8 different colors.  Solid color wire can be striped by pulling it by a felt tip marker.  For power stick with the convention that plus power is red, ground is black or green, and negative power is ( for me ) blue.


When you buy connectors, jacks, jumpers..... think about the colors and buy them in as many different colors as you can get.  The Pamona stackable banana plugs I recommended above used to come in about a dozen different colors, seem hard to find now.  


Ribbon cable comes in a multitude of colors, peel off what you need, sometimes it is handy that you can get more than one conductor in a unit.


If you need more colors for things like binding posts the paint for plastic models ( cost 15 cents when I first bought them ) can be useful.  For fatter cables you can use colored electrical tape ( like: http://www.amazon.com/3M-Electrical-Tape-9-Pack-Color/dp/B000PHGM14/  or  http://www.amazon.com/Duck-299020-Colored-Electrical-Multi-Color/dp/B001B175J6 )  add a colored band to each end of the cable to create variants: gray with a red band for example.

Step 12: Test Points

Test points are places in the circuit that are easy to connect to and support a signal of interest in debugging a circuit.  The output of an amplifier stage might be a good place for a test point   A small loop of wire, then end of a component or a piece just soldered in to make the test point can be used as a point of attachment.  Make them as small as you can, but big enough for your smallest grabber.  When the circuit is working leave the test points unless they are in the way, to remove, clip off flush with the board.

Step 13: Keep It Neat

A messy breadboard is very hard to debug.  You connect up wires wrong, and have trouble tracing the leads.  If they are just the right length and hug the board they are easy to see and do not snag on test leads etc.  It can be a bit of a pain, but it quickly pays off.  Use in conjunction with color coding.  The same applies to more permanently built circuits.

It is unfortunately too easy to find terrible examples of breadboard wiring on instructables -- you guys clean up your act.

Step 14: Take Pictures

Take pictures of circuits either to debug or repair. Especially useful if you are trying to draw a schematic of an undocumented circuit. Take from both sides. By mirroring you can be looking at the bottom while looking at a picture that shows the location of the parts on top.  Those of you who are clever ( not me ) may be able to figure out how to make the two sides different colors and then superimpose to get an X-ray like view.  If you figure this out let me know.

 

 

 


Step 15: Preset Strippers

Some strippers, particularly cheap ones are adjusted with a nut and bolt.  Usually a pain to get just right.  When you get them just right for a size of wire you commonly use, set them up tight, label them, and then don't change them.  Need another size  - use a different pair these are the cheap guys.  Most of us commonly work with a small set of wire sizes so we should need only a few pairs. 

Step 16: Use Needle Nose Pliers

When you push a wire or component lead into a breadboard, it often does not want to go in, so the lead crumples up.  Make it a habit of using needle nose pliers for the insertion.  Grab the lead just far enough from the end to insert it all the way, then push.  Works much better.  Of course there are lots of other uses for the pliers.  Harbor Freight has reasonable pairs cheap.

Step 17: Soldering Tips

  • Unfortunately solder with lead in it works better than the newer lead free solders. I normally use it but try to stay out of the fumes.
  • Solder does not make a very strong joint, best if you have a mechanical joint first, but often this is hard. Also try to maximize contact area of the joint to make it stronger.
  • Clean parts, particularly if old or oxidized before putting in place, I like 600 grit wet or dry paper, never use steel wool near you electronics work place.
Lots of tutorials out there on soldering, some are even good.  This is not a tutorial just a set of tips:
 
  • If the solder is not "sticking" a little scraping with a sharp blade may help. A bit of extra flux ( non corrosive please ) may also help.
  • Inspect all joints just after soldering. With point to point wiring where the solder provides the only thing holding the joint together try ( not too hard ) to pry it apart.
  • Keep the tip of the iron clean, damp sponge is fairly standard, wipe most every time.  Good tips are often plated, do not get too aggressive and remove the plating.
  • Remember solder when liquid tends to move towards the greatest heat.
  • Pre-tinning is often helpful, always consider doing it.
  • A temperature controlled iron is so much better than one that is not.  Need not be really fancy.  One in the picture is 40 years old, replaceable tips, still available.

Step 18: Miscellaneous Tips

Not quite sure how to catogarize these so put them here:
  • For integrated circuits and microcontrollers, use a socket rather than direct mounting of the component.
  • For experimental circuits assemble and test one stage at a time.
  • Power up without the chips and check voltages like power and ground.  Also check continuity.... to make sure what you built is what you planned.
  • Feel the chips to see if they are running hotter than they should.
  • Powering up from a current limited power supply often keeps in some of the magic smoke.

Step 19: Power

Use wall warts ( the little blocks that plug directly into the wall and provide power ).  Why?  Someone else has built most or all of the power supply and you are safer without any line voltage in your project.  For 5 volts a “usb” power supply is cheap and they are ubiquitous. A usb hub with a bunch of ports and external supply will let you power multiple projects at once. ( By the way the idea of building “usb” projects like fans and leds  and plugging them into your computer  is sort of foolish, usb is universal serial bus, these projects are just using the power lines, nothing serial about them. It is generally not a great idea to use a $500+ computer as a power supply. /rant ) Be careful to check the ripple and regulation of the supply, many are very poor.  Consider adding a regulator ( next tip ).


Three terminal regulators are incredibility easy to use.  LM7805 and similar parts are typical.   They are  often “short circuit proof”, use low parts count, come in many voltages ( or are easily adjusted )  and cheap.  Many an instructable has been published basically using the circuits that come right is the datasheet.  Adding to the back end of a wall wart makes a badly regulated wall wart behave, at a slightly lower voltage than the wall wart name plate.


Use batteries.  If you need to be unplugged.  If you are connecting your project electrically to a person or animal, then it should be battery powered.  This can save a life.  This applies to a computer as well, do not plug in and connect to a living thing.

Step 20: Cases for Your Project

On instructables you see a lot of projects that are not in cases.  This is, in part, because cases can be expensive, hard to find, and tedious to implement.  But a nice project deserves a case, and if the voltages are high pretty close to mandatory.  


On useful feature of a case is that the material is easy to work ( wood, aluminum come to mind ) and thin enough so pots switche, binding posts etc mount nicely.  A case that is mostly unfriendly, say steel, may be OK if you use an aluminum or plastic face plate.


You should scavenge for cases, I use old tea tins ( see  Tea Connector for Serial RS232 Cables by russ_hensel  https://www.instructables.com/id/Tea-Connector-for-Serial-RS232-Cables/  ) metal cookie boxes, plastic file cared cases and even plastic jars.  Altoid tins are popular for smaller cases ( like the classic minty boost. ).  If you salvage some piece of equipment always consider saving the case.


There are some tools that are useful for case work.  You should know what, drills, files, nibbling tools, reams, step drills and chassis punches are.  Then you can decide which to use.

Step 21: Breadboards

Great for prototyping, not so great for permanent projects as the parts and wires have a tendency to fall out. You can recreate it with a custom printed circuit board, or use point to point wiring on .1 inch perf board ( link ). There are even pre printed circuit boards ( like:


) that pretty much mimic a proto board but where you solder the component in.


For tips on using bread boards see my instructable:  Comprehensive Guide to Electronic Breadboards: A Meta Instructable by russ_hensel  https://www.instructables.com/id/Comprehensive-Guide-to-Electronic-Breadboards-A-Me/

 

Step 22: Diode in Power Connection

If you are powering your circuit from a power supply or similar it may be easy to connect the supply backwards. This may let the magic smoke out of your parts. If so put a diode in the supply line to block reverse voltages.

 

 

Step 23: Electricity Can Kill

But it should not kill you. Under 30 volts things are pretty safe. Dry hands and care help. Grounding yourself is not a good idea, if you do it for ESD issues do it through a high value resistor.  Shocks across the chest are very dangerous because that is where most of us keep our heart. Keep one hand in your pocket and you will not get a shock across your chest.

Step 24: Make a Circuit or Buy an IC?

If you a working on a project sometimes you will end up designing something that may seem a bit complicated.  Two examples:  a high side driver or a high side current sensor.  Both can be done without great trouble, and perhaps with parts you have on hand.  But also consider using an integrated circuit for the task.  Both of these have fairly cheap and simple to use IC that you can just buy.  Find the datasheets and any application notes.

Step 25: Plugging in Old Equipment

Old equipment that has been out of use for a long time may fail, and dramatically if the old electrolytic caps are shot. Some people just recommend that you open up the equipment, rip out the caps and replace. Sometimes they can be saved with the right start up procedures.

The basic idea is that in an electrolytic cap the dialectic is formed by the interaction of the chemicals in the cap with the applied field. The dialectic fades away with time but can be rebuilt by gradually applying a voltage. Google reforming electrolytic dielectrics.

Methods to do this vary, the simplest is to plug the device into a variac and slowly bring up the voltage. A meter across the cap is very useful.

The ideal method from the point of view of control is to break the v+ connection on the cap. Then connect an external power supply ( perhaps through a high value resistor ) and measure both the current and voltage for the cap. Slowly bring up the voltage. Watch the current, it should go to a very low value. Keep increasing the voltage until you reach the working voltage of the part and you are done. It the current stays high, both you and the cap are done. This process can take from perhaps 5 minutes to an hour.

I used this technique in:  A Tale of 3 Oscillators – Fixing Old Electronics by russ_hensel  https://www.instructables.com/id/A-Tale-of-3-Oscillators-Fixing-Old-Electronics/

Step 26: Tips on Instructables

Some instructables have been written as electronic tips, I will not find them all for you ( consider searching ) but here are a few I think are useful:

  • Watch for more instructables by me!  Already working on 2 more on electronics tips.  Why not subscribe?