Kevin Ross email@example.com
This is the first Basics column I have written for quite some time. I hope you get a chance to go back through some of the previous issues. There is some pretty useful information in them. Check the Front Page of the Encoder.
One common question that everyone has is what sort of tools are needed to get starting in assembling electronic projects. This is a good question that deserves a good answer.
I am going to assume that if you are starting with nothing, then you probably will want to get a good mix of tools, yet at the same time rushing out and spending thousands of dollars wasn't what you had in mind. So, I went shopping around, and have a list of things you might consider adding to your toolbox. All of the tools I am going to suggest are decent quality, but fairly low cost. I was hoping to put together a decent toolbox for under $100. I will keep a running tally as I go through these articles.
The other important point is that you should be able to purchase these tools without having to pay too much for shipping. As it turns out, most of these are available at your local Radio Shack store, or through Tech America. You can also find them at Digikey, Mouser, or many other stores. I am going to point out a lot of Radio Shack stuff since you can probably find a store and see them in person before you buy.
If you want to start a great argument, get a group of experienced project builders together and ask them what the best tool is. A project builders toolkit is a very personal item, and something they will defend at all costs! You are about to get my opinion on the subject, and I think most people would agree that what I propose is adequate for starting out.
I am also assuming that you already have basic tools such as screwdrivers and pliers, so I will not go into those.
I have written several times on the SRS mailing list about soldering irons. My theory on soldering irons is that you are either going to be soldering every now and then, or you will be soldering A LOT. If you are planning on soldering a lot for the next few years, I recommend making an investment in a good iron.
Pointed or conical tip
If you are just starting out, or don't solder often, then I highly recommend getting a 15 watt iron with a grounded tip (Radio Shack #64-2051). The grounded tip will prevent electrostatic discharges. An ESD is a great way to kill your project before you start. I also recommend a fairly small pointed or chisel tip for your iron. This iron costs about $8.00 and does a decent enough job if you are just starting out. You should be able to build most electronic circuits, including doing some surface mount work. There are other, and cheaper, soldering irons at Radio Shack, but the points are usually too big for most uses and the tips are not grounded. This iron is of OK quality, and should last you for quite a while. Since this is an $8.00 iron, you can expect that it will eventually wear out. The tips are not very high quality. I would expect you to get 100-150 hours of soldering out of an iron like this. At $8.00 a pop, this is quite a good bargain, since you can just get a new one after a couple of years. I seem to recall paying $8.00 about 5 years ago (1995), so the prices seem to be pretty stable.
One issue with irons of this type is that they are not temperature controlled. They always put out the full 15 watts of heating. They will, and do, eventually overheat if left sitting for too long. This usually causes the tips to degrade at a faster rate. An iron like this isn't something I would feel safe leaving on while I went away for several hours. I would recommend using a solder iron stand, such as the one pictured below on the Weller iron. They help dissipate some of the excess heat, and also prevent your iron from touching something you didn't intend!
If you visit the hardware store, you will find a whole array of different irons with different powers. Bigger wattage really doesn't mean it is better for electronics! For the most part, you want to keep the wattage as low as possible yet still be able to do the job. I don't recommend soldering 'guns'. Most of them are dual temperature (50 or 100 watt), have large tips, and are not well suited for electronic work.
You can use irons up to about 30 watts for electronics. Nothing at all wrong with selecting a 25 watt, for example. However, I wouldn't typically recommend going above 30 watts unless it is temperature controlled. You can often find a good 25 watt Weller iron at the large hardware stores for a decent price.
If you plan on doing a lot of soldering, then you should probably consider investing in a good quality temperature controlled soldering iron. There are lots of them on the market. I bought a Weller WTCPT about 6 years ago, and have been extremely happy with it.
As you can see from the picture, the iron has a base station, a sponge pad, and an iron holder. I happen to use a 700 degree 1/16" screwdriver tip on my iron, and have been extremely happy with it. I use this iron at least 10 hours a week, sometimes up to 30 hours a week. Things I like about it are that the cord is extremely flexible, so it tends to stay out of the way. The temperature control means I feel comfortable leaving the iron on all day long. The downside is that the base station is a little big, and this really isn't a 'portable' unit like the Radio Shack iron. It also cost over $100. Keep your eye out, this iron goes on sale quite often at most of the large suppliers. It usually costs about $135 or so, but I bought mine for $99.99 at Radar Electric. I have seen it on sale at Active Electronics as well.
Soldering Iron Summary:
15-watt 'pencil' style with a small grounded tip is best for general electronic work. Radio Shack 64-2051 is a good choice.
Temperature Controlled is the best way to go if you can spend the money. Weller is one of the biggest and best manufacturers. You can find Weller parts anywhere. Ungar is also a good choice.
Suppliers for low priced irons: Radio Shack (64-2051 $7.95),
Suppliers for Weller WTCPT: Tech America (910-2469 $139.99), Mouser (578-WTCPT $134.27), Digi-key (WTCPT-ND $136.28), Active Electronics, Vetco (Bellevue, WA)
Budget: $8.00 for starters, $100 for a good temp controlled iron.
If you are going to work with digital circuits, then one of the single most useful tools you can invest in is a Logic Probe. This would including working with Microcontrollers, or anything in the '74xxx' family. This probes function is to tell you the digital state of a circuit. Digital circuits are higher 'high' or 'low' (on/off, +5/0, etc). A logic probe allows you to test the state of a pin or trace just be touching the probe to the circuit element in question.
A Logic Probe in action
For digital circuits, a logic probe is extremely valuable as a debugging aid. Not only will it show you the current state, but it can also tell you if the state is changing. Sometimes a circuit will normally be high (on), but brief pulses will be emitted. These pulses are difficult if not impossible to detect with a volt meter. The logic probe is designed to help you out by beeping and lighting up whenever the state changes. This is a great yet inexpensive way to determine if your circuit is working. Radio Shack offers a decent logic probe for about $15.00 that is a tough deal to beat. You can get similar devices from other sources as well.
Suppliers: Radio Shack (22-303 $15.95), Tech America (220-303 $17.95)
A decent multimeter should be on everyone's list. This basic of all measuring tools handles the measurements of voltages, resistance, current, and depending on the model, a whole slew of other useful things. There are two basic flavors of multimeter on the market: Analog and Digital. Either will do the job, but each have their own quirks that make them unique to use.
The most common uses for a meter are to measure voltages and checking for continuity. Voltage ranges are typically under 100 volts. Continuity can be checked either with a resistance measurement, or using a continuity function. Either work fine. Much less important features include diode checks, transistor measurements, capacitance measurements, and a few other oddball items. For most of us, this last group of measurements really aren't important, nor worth spending extra money on. A meter that handles around 400 volts is pretty common.
A small, inexpensive Analog meter
Analog meters, such as the one shown above, are cheap and widely available. With this unit, you have the ability to measure voltages and resistances. Analog meters require a little more skill in reading the scale and setting the meter up. The voltage range, for example, needs to be set by the user. I bought the meter above at the hardware store for about $6.95. I have used it quite a few times, and it seems to do the job.
A digital meter is, in my opinion, a better investment in the long term. They do all of the basic functions at the Analog meters do, but they are easier to read, most have auto-ranging, and they have a great feature called a continuity checker. That allows you to track down short circuits or broken circuits. If there is continuity between the two leads, then the unit usually beeps or has a tone. Using the tone, you can quickly trace through a circuit looking for errors.
Radio Shack 22-802
The prices for a decent multimeter range from about $14.95 to $100. You should be able to get a good meter for about $30. Last time I was in Radio Shack, I thought the $24.99 #22-802 meter was a pretty good buy. It has all the basic functions for pretty cheap. This includes the continuity check They had a couple others that were a small step up, but for the price, the $24.95 meter seemed to handle all of the usual measurements. This particular meter does not do current measurements, however.
Radio Shack #22-803
To get the current measurements, the next step up at Radio Shack is the #22-803. It does do current measurements up to 400mA, but costs $39.99. Once you pass the $40 level, the options for different meters go up quite a bit. Which unit you buy is mostly up to your budget concerns. If you get super serious about electronics, you will probably buy a > $100 unit sometime in the future. Until then, these are fine units.
Suppliers: Radio Shack, Digikey, Mouser, Home Depot
When I first started doing electronics, I used a rather rag-tag assortment of tools. Actually, my first wire stripping tool was a 20-24 gauge gap between my two front teeth! My mother, who worked for a dentist, promised me any amount of extra allowance if I would buy and use a pair of wire strippers. I immediately went out and spent $40 on a really cool wire stripping tool. It was big, full featured, and really didn't work very well. Thus, I ended up using my teeth for years.
After quite a bit of experimentation, I finally found two tools that I use quite a bit. Luckily, these turn out to be the cheapest tools on the market!
Both of these tools run about $4.00, and seem to last quite a while. I use the cutters quite a bit during the week, and they last me at least 6-8 months. They will last most people a couple of years. At this price, you can afford a few pairs!
The wire strippers have an adjustable stop. I have mine set for 22awg. Once you get used to them, the stop really isn't used much. I use the same settings to strip wire, cable jackets, and even Romex.
These really aren't a Radio Shack exclusive item. These are cheap, made in Taiwan tools that seem to be resold under several brands. Radio Shack, however, seems to have the best price.
Suppliers: Radio Shack, Vetco, Mouser, Digi-key
Budget: $8.00 for the pair
For soldering, there are a few extra tools and supplies that I find quite useful. The first and foremost is a 2oz can of Paste Flux.
Paste Flux is used to help your solder flow, clean the tip of your soldering iron, and for mounting surface mount parts. If you have ever had a cold solder joint that you just can seem to sweat, then you are really in for a treat. Add a small amount of this paste flux to your iron and the solder will flow like new.
It amazes me that half of the electronic guru's in the world have never heard of or used this stuff. However, just about any TV repair or other workshop that does solder rework will have a tin of this by ever soldering iron. A 2oz can is going to last you at least 5 years. For $2.00 or so, this is by far one of the most important investments you can make.
I think the second most important supply is solder wick. If you have ever made a mistake during assembly and needed to remove a part, solder wick is for you.
As you can see by the pictures, these are all materials I used on a regular basis! Solder wick looks a lot like coax cable braid. When you heat it along with your solder, it will tend to suck all of the solder out of the joint. This is great when you need to remove a part from a circuit board. It will usually grab at least 95% of the solder out of the joint, making it much easier to get the part out. You can use this in place of those pesky solder suckers which I always have a tough time using!
You can buy a small 5' roll of solder wick at Radio Shack (#910-0039) for $2.50 or so. I recommend something in 0.060-0.085 width range. This will last you quite a while. If you use a lot, then I suggest Digikey or Mouser. The Chem-wik roll in the picture cost me $7.00 for 25'.
A Box Fan blows the smoke away
The final soldering tool I like is a small box fan. Since I solder a lot, I am always a little concerned about inhaling the smoke. Flux and Solder both put out a fair amount of smoke. This little box fan is quite handy to use. I place it near my soldering area, and turn it on when ever the iron is on. I aim it directly at the soldering work I am doing. Any smoke that tries to go straight up into my face is blown off to the side where it disperses into the room.
Recently, I bought a fume extractor. This was a $200 contraption that sucks the soldering smoke through a set of filters that catch quite a bit of the oily residue that solder puts out. I decided on this due to the shear amount of soldering I do while assembling the kits I sell. The box fan, however, is still part of my toolbox. It is especially cool since I take it with me to SRS meetings or to friends houses when I know I will be soldering. It is a 5 volt fan, so it runs great on batteries.
You can often times find a small box fan like this at Mouser, most surplus stores and catalogs, or Digikey. A 12v fan is available at Radio Shack. You really don't need a big fan. A slight breeze does the trick.
Suppliers: Radio Shack, Mouser, Digikey, Vetco, Active
Budget: $8.00 (Fan), $2.00 (Flux) $3.00 (Solder Wick) == $13.00
These are just a few of the tools I use almost every day. There are, of course, many many other tools that we all use on occasion. I have spent thousands of dollars on tools, but end up using about $150 worth of them on a regular basis.
If you bought most of the things on this list, you would end up spending about $80.00 or so. That is under my $100 spending limit and should get you enough tools to get started.