Creating your own complete electronics lab at home is essential if you are passionate about electronics. Learning electronics is more about practicing and experimenting. Like Aristotle said in one of his quote:
For the things we have to learn before we can do them, we learn by doing them.
They are a couple of tools which are essential in electronics and needs to be in every maker’s electronics lab. But nowadays, they are so many choices and brands out there that it might be difficult to find out which one to choose from. In this short tutorial we will show you what are the most important characteristics to look for when selecting electronics tools for your newly created electronics lab.
Why having an electronics lab at home matter?
Most of the experienced electronics engineer will agree that the best way to learn electronics is by designing and testing circuits. It is possible to use electronics simulators to have and idea of how a circuit behaves and it is even recommended to start with. But most of the problems happens in practice. Having an electronics lab at home will help you experiment and understand the practical side of making electronic circuits.
The best experiences that I had when starting to design circuits where when I was disassembling the different gadgets that I had at home. By doing so, I have learned so much on the structure of electronic devices and what they were made of. A good resource to see different electronics devices tear-down without having to do it yourself is ifixit.
In short being able to test and probe the different circuits that you will come across really helps to get a practical experience. It will then be easier to design new circuits the proper way from scratch.
What electronics tools do you need?
Below are 4 basic tools which will help you in your different projects.
[ Stay tuned for the second part of this tutorial which will be more detailed, with more tools ].
1 – Digital Multimeter
The basic functionality of a digital multimeter (or DDM) is to get certain values from an electronic circuit. It is used to measure voltage, current, resistance, but also to test the continuity of traces and wires.
If you are looking for the best multimeter in the market for your electronics lab, well there is not really such a thing. They have different characteristics which needs to be considered separately for each use case.
The main question to ask is: What is the multimeter going to be used for ?
If you are a professional, you would like to have one which is reliable, precise and functional. Obviously it will cost more than one intended to be used by a hobbyist.
In any case, here are the main characteristics to consider:
The resolution is the minimum value a digital multimeter can measure. As most of the DMM now have a digital display, the resolution is the number of digits which can be shown on the screen. The resolution is generally between 3½ and 4½. For instance a DMM with a resolution of 4½ means that it has 4 digits which can display a value between 0 and 9 and one last digit which can be either 0 or 1.
The accuracy is expressed in % of the reading. So for example a 0.1% accuracy multimeter will output 9.9V for a 10V signal. In fact, that is not exactly correct because the previous example is only taking into account one part of the accuracy. There is also an error due to the internal circuit, the ADC and the display of the DMM (Least significant digit error or LSD error).
The complete formula is : Accuracy = ± (% of reading + LSD error).
- True RMS
True RMS multimeters are able to measure sinusoidal and non-sinusoidal AC waveform. The value given by the multimeter is equivalent to the DC (Direct Current) value of the waveform. It is generally recommended to have that function as it is extremely useful when dealing with periodic signals.
- Input impedance
Standard impedance are around 1MΩ . The higher the impedance is, the less perturbations the DMM will introduce when it is connected to a circuit.
2 – Soldering Iron
Choosing a good soldering iron is essential. It is one of the most important thing to consider if you are planning to have an electronics lab at home. We have all, at least once, ran into a situation where we tried to solder a component using a “not so appropriate” soldering iron without great success. They are many factors to consider before choosing a soldering iron. Here are the most important ones:
- The wattage
The wattage provides an indication of how powerful the soldering Iron is. If the wattage is too low, it might be difficult to perform certain tasks like soldering relatively big wires on a circuit. In general, while certain makers uses soldering irons with power between 15W and 35W, professionals can go as high as 80W.
The ability to change the tip of the iron gives more flexibility. For soldering small components like SMT (surface-mount technology), a small and thin tip is more suitable. They are usually relatively cheap. So having 3 or 4 tips of different sizes is a good option.
- Temperature control option
Some of the Irons have the option to manually adjust the temperature of the tip. If possible, It is recommended to choose an iron with that functionality. Setting up a too high or too low temperature can either result in a bad solder joint or an overheat of the component. Before soldering a component, always double check the maximum allowed temperature and set the soldering iron temperature accordingly.
From experience, “Weller” and “Circuit Specialists” are suitable for most of the jobs and their soldering irons are really fun to work with.
There is a soldering Iron for every budget!
$10 to $30 for a soldering pencil. $20 to $70 for a soldering gun. $40 to $200 for a soldering station. Finally above $250 for a complete rework/ repair system.
3 – Digital Oscilloscope
An oscilloscope is an indispensable tool for anyone interested in observing a signal which changes over time. They have integrated features that allows to measure average Voltage, Frequency, Duty Cycle, Amplitude of a signal and much more. Selecting an oscilloscope will mainly depend on it usage. Here are the things to consider :
The bandwidth is the maximum frequency at which the oscilloscope can measure a signal with a minimal amplitude loss. At the specified bandwidth frequency, the amplitude of a sinusoidal signal will be attenuated by -3dB (dB stands for decibels).
In short the oscilloscope will display 70.7% of the amplitude of the real signal at the specified bandwidth frequency. For signals with a frequency higher than the bandwidth, the amplitude of the signal will be even more reduced.
The bandwidth should be chosen to be greater than the maximum frequency of the measured signal.
- Digital vs. Analog
Since the scientist Karl Ferdinand Braun invented the oscilloscope in 1897, they have been a lot of changes since then. The technology has evolve from analog to digital, which brings up more capability.
It enables the makers to benefit from functions such as Signal processing, Waveform analysis, Signal recording and so on… Nowadays, digital oscilloscopes are growing in popularity and are the most widely used. They use the ADC of an integrated microcontroller to sample and convert the analog signal to a digital signal.
You will still be able to find analog oscilloscopes, but the choice is limited as they are based on old technologies which are only supported by few manufacturers. It is then preferred to use a digital oscilloscope nowadays, as they have more functionalities than the analog ones.
- Number of channels
2 to 4 channels are the most common. Usually when dealing with different signals which are temporally related, it is a good idea to have all the signals plotted on the screen at the same time. If more channels are needed, it is possible to find an appropriate oscilloscope with high end suppliers like National Instruments (Check the PCI-5150 from National Instruments for more details).
- Sampling rate
Sampling rate and Bandwidth goes together even if they are not directly related. The sampling rate is the number of time per seconds the signal is acquired. It is usually expressed either in MSps (Mega Samples per second) of GSps (Giga Samples per second). Because of the Nyquist-Shannon theorem, the sampling rate is chosen to be 3 to 4 times the bandwidth in order to avoid aliasing and to provide an accurate reconstruction of the signal.
The resolution is the the number of bits returned by the internal ADC of the oscilloscope. There is a simple rule for choosing the resolution: The higher, the better!
Choosing a high resolution will allow to measure small changes in the input voltage.
The minimum voltage that an oscilloscope can measure is determined by the formula: Vmin = Input Range/2b
Where b stands for the number of bits of the ADC.
- Input impedance
The input impedance is noticeable when measuring high frequencies. At those frequencies, small resistances, capacitors or inductances can affect the measurement of the signal. Every oscilloscope adds a certain impedance to the circuit it is connected to.
Basically, when connecting an oscilloscope to a circuit, there is a resistance of the order of a MΩ in parallel with a capacitor in the pF range which are added to the circuit. Generally, using a probe with your digital oscilloscope will help attenuate the effect of the input impedance. Probes with ratios 10:1 are the most common.
4 – DC Power supply
It is the ideal equipment to power your projects. Choosing an AC to DC power adapter is quite straightforward. They are 3 characteristics to consider :
- The Output voltage rating
It represents the maximum output voltage that the power supply can deliver. Power adapters are available either in unregulated or regulated voltage. It is most of the time a good idea to choose a regulated voltage output. There is a wider rage of voltages to choose from compared to the unregulated version which only provides a single voltage.
- Maximum output current
Each power adapter has its limits in term of the maximum current that it can output. It is important that the load of the circuit is less than the maximum output current of the power supply. Not meeting this requirement will lead to the power supply failing when it is connected to the circuit.
Ripples are variations which will be present in the output signal of the power supply unit. Even if a regulated output power adapter is used, those ripples will still be observed. The ripples are greater in non-regulated DC power supplies. This is yet another reason to choose a regulated power supply from the start for your electronics lab.
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