23 Jan 2013

The lab : tools and test instruments

The lab

Even if you got the best skills, you can do next to none in electronics without a minimum of tools and instruments. In this post I will present the tools and instruments I have to work. Keep in mind, some of the things here are fancier than what you can get for a cheap price on the internet or at the hardware store. Though, this should give you an idea of what you might need to work efficiently.

Here is what my lab set-up looks like

Having a little workbench is a nice thing, because you want to get everything you need in your workspace (and you don't want to mess the dinner table). If your job is not finished, you can leave your stuff there without anyone to move your stuff around.

The tools and instruments

Multimeter

At first, you need to get a multimeter. You will then be able to read voltage, currents and resistance value. More advanced multimeter will let you take RLC measurements (inductance and capacitance), display the frequency etc... A pretty useful feature is the continuity test (beep a connection). This test let you know if the contacts you probe are shorted. This can be useful if you have a PCB (Printed Circuit Board) and want to look where are the grounds connections on the differents components.

Here is my benchtop multimeter (left) and power supply (right)

Power supply

Next would be a power supply. A poor man power supply (wall wart) can be found almost anywhere, but the problem with these is that they output a constant voltage (we will later how we can change that, cue : LM317). In a lab setup, we want a variable voltage power supply. The model shown (100W) is 0-36V with a 3A maximum output. The good thing with these supplies is that you can control the maximum allowed current output. This is really helpful when you want to protect a component by limiting the maximum current to be a little bit under the current rating of the component. Let's say you have a 1A transistor, not limiting the current would destroy it in case of a short-circuit (in this case 3A would flow).

Breadboard

The prototyper best friend, here is the protoboard. When you are not sure if the circuit you are building will work (in my case 90% of the time), you're better to make a prototype first. Most of the through hole components (diodes, resistors, caps, leds...), integrated circuits in DIP (dual in-line) package and wire should fit in.

An empty breadboard

Soldering iron/station

For through hole component soldering, you don't really need the best iron on the market. But when it is the time to solder tiny SMT (surface mounted) components, you will need a soldering station. I think it is a good choice to invest in one with numeric display and temperature feedback. Mine is a WESD51 from Weller : excellent and reasonably priced (200$). I aslo recommend buying a few spare soldering iron tips (around 4$ each). On the picture, you can see other accessories : tube of solder, desoldering braid, liquid flux pen, flux dispenser and PCB cleaning pen. The flux helps distributing the heat when soldering SMT IC.

Weller WESD51

Oscilloscope

Okay, this one is a bit more pricey. The oscilloscope is not really necessary to get started, but is a great addon in the future. It is your best friend to analyse analog and periodic signals and to debug serial data transfer. In other words, every signals that is not static (not measurable with a multimeter). You can do more advanced stuff to : get the frequency content of a signal (FFT), perform calculation between two signal (addition, substraction) and some other goodies. Mine can save screenshot on a USB drive, I think it will be useful in my future tutorials.

BK Precision 2530B entry level oscilloscope (450$)

Other tools


These are needed to cut and strip wires. The long nose plier is useful for bending resistor leads


For robotics, you need different sized screwdrivers 


Don't forget the wires, in different colors. Digital calipers are useful for precise measurements


Conclusion

That's all for tonight folks. Phew, that took me a while to write!
As you can see, a lot of stuff is needed to get serious in electronics. I'm sure it is possible to get working with less than what I showed here, but I think this novice lab is what it takes to get started.

Thanks for reading and see you soon!

4 comments:

  1. Belle liste pour commencer!
    J'étais curieux de connaitre ton avis sur un oscilloscope : le DSO nano 3 (http://www.seeedstudio.com/depot/dso-nano-v3-p-1358.html?cPath=174)

    je comprend que ce genre de gadget n'offre pas la même précision, BW et tout qu'un 'vrai', mais crois-tu que cela peut etre suffisant pour débuter? (ou ce n'est quun gadget qui ne vaut pas le cour)

    Bonne continuation!

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  2. Hi Claude, the DSO nano is a good device for beginners as well as intermediate users. One of my friends got one of these and is satisfied with the quality of the product. The DSO nano v3 has a 200kHz bandwidth, which is okay for most applications. The 25MHz bandwidth of the BK 2530B justify the cost of the oscilloscope.

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  3. Thanks! I will consider both

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  4. Regarding DSO nano I got one. It is fine if you need to read low frequencies. Mine is able to read signals up to 1 MHz but measurements at this frequencies are not as good as expected. On the other hand, this is one of the cheapest you can find.

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