Bench Talk

In the previous blog about essential tools for electronics, I mentioned some of the more basic items. As you do more advanced electronics, and sometimes to better understand the basics, you would do well to have the following tools. They are not really needed for building basic circuits and playing around with Arduino projects and the like, but as you start to expand into more complex technologies, you will find these tools extremely helpful:

1.         Benchtop Oscilloscopes (50MHz, 2CH, 1GS/s) - For some, the acquisition of a digital oscilloscope is akin to reaching electronics nirvana. An oscilloscope is no doubt an extremely useful tool if you can master its use. Digital oscilloscopes are driving down the cost of basic test equipment at breakneck speed. With decent scopes hovering at around the $500 mark, they may still not be feasible for every open source maker, but if you are serious about doing even the most basic work signals, such as projects utilizing infrared transceivers, then an oscilloscope will serve you well during troubleshooting. A decent digital oscilloscope for many makers will have a bandwidth of 50MHz, offer two channels, and offer 1G/s capture rate. Some basic scopes even offer the ability to save waveform captures to a USB thumb drive, which can be quite useful for those collaborating on an open source project with team members scattered around the globe.

A fantastic entry-level oscilloscope to check out is the Tektronix TBS1052B

A lot further up the chain is the Teledyne LeCroy WaveAce 1001. While both offer great features at relatively reasonable price points, including 2GS/S sampling rate and USB connectivity, there are other differences you should consider. The WaveAce comes in models that have bandwidths that reach up to 300MHz whereas the Tektronix model recommended here peaks at 200MHz.

2.         Function Generator (B&K Precision .05 MHz - 4 MHz) - If an oscilloscope allows you to peer into a circuit to watch signals interact with components, then a function generator (also sometimes called a signal generator) allows you to inject a known, well-defined signal into a circuit in hopes of stimulating the circuit to respond in a predetermined manner. Hopefully the response is based on how the circuit was designed and constructed. A decent function generator that can meet the needs of most open source makers will probably run you a few hundred dollars. It should be able to produce signals from 0.5Hz to up to 5MHz sine waves. Additional waveforms such as square, saw tooth, and ramp waveforms may operate at slightly lower frequencies. There are also some fairly low cost signal generators that can produce arbitrary waveforms that you first design in computer application, then transfer to the function generator via a USB interface.

Figure 1: The B&K Precision 4003A Function Generator is a powerful yet inexpensive option.

Check out the B&K Precision 4003A model for powerful yet inexpensive option for a good function generator.  If your project is going to remain in the audio domain, you can try a less costly audio generator instead.

3.         Logic Analyzer - Most entry level oscilloscopes are great for analyzing analog signals but can leave a lot to be desired when trying to analyze digital signals. A logic analyzer can be thought of as an oscilloscope that specializes in observing and analyzing digital signals. The peaks and valleys (aka the 3.3V/5V 1’s and 0V 0’s) of digital signals concatenate together to form specific symbols based on predefined protocols such as I2C or SPI. It is much easier to troubleshoot a circuit looking at the string of symbols that are represented by the 1’s and 0’s than analyzing the individual 1’s and 0’s themselves. A logic analyzer serves as the translator between man and machine. Just like most of the tools mentioned thus far, logic analyzers come in variety of configurations and price points. I would consider 4 capture channels, 100MS/s digital sample rate, a 25 MHz maximum signal, and the ability to handle 1.8V to 5.5V signal levels as adequate for most open source maker applications.

The Saleae Logic Analyzer is a popular choice amongst the maker community. Another option to check out comes from EasySync and is their ES-DLA-8 analyzer.  Features to consider when selecting a logic analyzer include sample rate, bandwidth, memory depth, and the number of channels.  Many analyzers come in 4, 8, and 16 channel options.