Digilent Analog Discovery 2 Review | Workbench Wednesdays

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The Analog Discovery 2 combines all the equipment found on a typical electronics workbench into one small package. It packs an oscilloscope, logic analyzer, power supplies, spectrum analyzer, and so much more. As impressive as the hardware is, the Analog Discovery 2’s software, called Waveforms, is fantastic as well. You can configure it for any measurement situation, and it has extensive scripting capability. See if you should be considering adding the Analog Discovery 2 to your electronics workbench.

My day job causes me to travel on a regular basis. Sometimes that means taking my circuits with me. I picked up an Analog Discovery 2 so that I could take test equipment with me. It’s a small enough box that fits nicely into my bag. The one significant trade-off is that it requires a PC to be functional. However, for travel, that works out great.

The key functions the Analog Discovery 2 provides are:

  • 2-Channel oscilloscope
  • 2-Channel function generator
  • Voltmeter (not DMM!)
  • 2-Channel Power Supply w/ negative voltage
  • 16 Digital Channels for Logic, Protocol, and General Purpose I/O
  • Network Analyzer (Bode Plots!)
  • Spectrum Analyzer
  • Impedance Analyzer

There are probably other functions, but that covers the major ones. Years ago, I reviewed the Virtual Bench from National Instruments. While the Virtual Bench has better specs than the Analog Discovery 2, the difference in price points is staggering. You can get the AD2 for $200-300.

Check out how some of the features work and my thoughts on this device in this Workbench Wednesdays review.

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Function Generator Basics | Workbench Wednesdays

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Generating signals with a waveform, function, or arbitrary generator lets you test all kinds of circuits. Learn how to get a function generator to output a signal, the 3 types of waveforms you can create, and which controls matter. James, the Bald Engineer, explains the difference between analog and digital generators.

The video introduction is my first attempt at doing an LGR style “Tech Tales” story. It is short with only a few images. However, it is something I would like to do more of in the future. My professional career started at Agilent right when they split off from Hewlett Packard. Most of my co-workers had been there while Bill and Dave still worked at the company. Even though the computer division took the name, Agilent was HP’s core: test and measurement.

Someday I hope to see an actual 200A. Their place in history has become legendary. Some people say that Disney’s Fantasia could not be produced without it. However, Bill (or Dave) set the record straight. Disney’s engineers could have used another piece of equipment, however, they did select the 200A.

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Logic Analyzer Basics | Workbench Wednesdays

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Logic analyzers capture digital signals and then display a waveform or list. Serial busses like I2C, SPI, or UART (Serial) can be decoded or triggered on when there are problems in your circuit. In this video, learn the basic controls you need to use (almost) any logic analyzer. You’ll learn how to set up a simple trigger, make measurements, and set things like sample rate or memory depth.

When I first graduated from college, I started as an Application Engineer for Agilent Technologies. Based in Austin, I supported computer companies like Dell, Compaq, HP, IBM, and Tandem. I helped their engineers set up million-dollar logic analyzer configurations to measure various PC busses.

I did embellish a tad during the introduction. Shown in the video is an HP 16500. While I did occasionally help program a trigger on these analyzers, my career really started with its successor, the HP 16700. Both were amazing analyzers for their time. It is mind-boggling to think that a small $150 USB-based device has very similar measurement capabilities to those old beasts.

Previously, I made a written Logic Analyzer introduction tutorial and benchmarked digitalWrite() with a Salee Logic 8. Contrary to what people have said, the LA2016 featured in this video does NOT use Salee’s excellent Logic software. However, the user interface is clearly copied from it.

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Spectrum Analyzer Basics | Workbench Wednesdays

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A spectrum analyzer displays signals in the frequency domain. To use one, you only need to know about four controls: reference level, center frequency, and resolution bandwidth. In this episode, see how to use a spectrum analyzer and determine the transmitting frequency of a device.

The example device is my microphone transmitter. It operates around 500 MHz with FM modulation. You’ll see how I step through the spectrum analyzer controls to find the exact frequency. At the end of the episode, I show some advanced measurements you can do with a modern spectrum analyzer. My favorite one is the demodulation. (more…)

Electronic Load Basics | Workbench Wednesdays

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During the Bench Power Supply basics video, I made use of my electronic load. An electronic load can sink current from power sources such as power supplies or batteries. Loads are useful to test a power supply’s design margin or verify a battery’s capacity. See how three different instrument options from ultra low-end to midrange to high-end compare. After this element14 Presents Workbench Wednesday video, you will understand how to use modes on an electronic load like constant current and constant resistance to make different measurements.

In the video, I compare three different types of tools: a $50 battery tester from eBay, BK Precision 8540 Electronic Load, and a high-end Rohde & Schwarz NGM202. They are all capable of acting as a constant current sink. In other words, you program the current and let the supply under test run. In the case of batteries, this mode is useful to test battery life. The 8540 and NGM202 both feature other capabilities like constant resistance which, as you can imagine, acts as an electronic resistor. The cool thing about using an electronic load as a power resistor is that some of them are capable of sinking up to 10s of amps.

After submitting the video to the producers, I realized I focused very heavily on batteries. More often, you use an electronic load to test power supply boards or modules. I wish I had shown those more, but it didn’t seem like it was missing until the end. So maybe in the future I can convert tools for measuring DC/DC power supplies? However, I did cover one topic significant to me. I show just how bad 9V batteries are, a topic which I like to come back to often. So I made sure to show off just how bad they work when driven past 100 mA. (It is terrible!)

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Bench Power Supply Basics | Workbench Wednesdays

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A bench power supply makes powering circuits easy and safe. Learn how to adjust basic controls like voltage. Finally, see how “current limiting” works (and why you should use it.) See how you can use built-in series or parallel tracking to increase a bench power supply’s voltage or current output. Last, if you are in the market for a power supply, do not forget to add some leads like mini-grabbers, alligator clips, and banana plugs.

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DCA Pro Transistor Tester Review | Workbench Wednesdays

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When it comes to transistors, there are only so many things a multimeter can measure. The DCA Pro from PEAK Electronics makes short work of testing parts like a transistor. This small device can determine pinout, component type, and essential parameters in a matter of seconds. Not only that, but it can be connected to a (Windows) PC and draw parameter curves.


Check out the video review to see how the device and software works. Then head over to the element14 page where you can download a zip file full of example parts I measured for you. Use the free DCA Pro software to open them.

You might also want to check out this MOSFET Curves post, which complements this video tutorial. Another resource you might find helpful on semiconductors, or transistors, is this post on MOSFET Myths.

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Measuring ESR with the PEAK ESR70 | Workbench Wednesdays Review

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There are three capacitor measurements you need to know how to make: capacitance, leakage current, and equivalent series resistance. Capacitance is easy to measure if you have a current limited supply or can use a resistor. Apply a voltage, then time how long it takes to charge-up. You might need to use an oscilloscope or even an Arduino for the second part.  Leakage current is the easiest of the three, apply a voltage (ideally through a resistor) for a few minutes, and then measure the current. ESR requires some special tricks. Since it is the resistance of the “wires” connecting to the capacitive element’s anode and code, you have to measure resistance without charging up the capacitor. (Otherwise, you get leakage.)

In the post Measuring Aluminum Electrolytic Capacitor’s ESR, I go through those methods in more detail. I also introduce the PEAK Electronics ESR70. It’s a pocket-sized instrument that measures both Capacitance and ESR. There’s a button you can touch, or it detects when a new capacitor is connected. Check out my Workbench Wednesdays review where I go into depth about how the meter works (and whether or not I like it.) Oh one bonus feature, it works while in-circuit!

As of this post, it has been almost six years since I first wrote about capacitors on my blog. The article was the Arduino GSM Shield’s capacitor has a serious design flaw. Wow, how time passes.

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Bald Engineer’s ESD Must-Haves | Workbench Wednesdays

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Electrostatic Discharge (ESD) damage can occur without you knowing it. That’s bad. However, the good news is that with little effort you can prevent it. Duratool has a kit of the most common tools for any electronics workbench. It includes a large mat, grounding cable, wrist strap, ESD-safe cleaner, and a simple electronic tester. Don’t get shocked by electrostatic discharge; add these simple tools to prevent it.

This review is on a kit that includes:

  • Large ESD Mat
  • Ground Cable
  • Wrist Strap
  • Wrist Strap Tester
  • Electrostatic Discharge Mat Cleaner

Even if you aren’t interested in ESD, you might want to watch the first 30 seconds. Hopefully, the clever thumbnail explains why. 🙂

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Tenma 72-2660 Portable Hand Held Supply | Workbench Wednesdays

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The TENMA 72-2660 portable power supply offers bench supply capability in a backpack friendly package. The single output is capable of 45 watts with up to 30 volts and 3.75 amps out. The built-in USB ports offer an easy way to power 5 Volts Arduino or Raspberry Pi projects while limiting their current. See how this portable supply performs, the things the Bald Engineer likes about it, and the points to consider before buying

This $100 power supply, model number 72-2660, is cool. It’s about the size of a digital multimeter but can output 45 Watts. Both voltage and current are adjustable. It can output up to 30 volts and 3.75 amps, but not at the same time. It does have a flaw in its design though. Fortunately, I was able to find and apply a fix for it. Overall, if you want a portable adjustable supply, this one is worth checking out.

If you are new to bench or lab power supplies, check out this bench power supply basics video.

To answer a common question: yes, I did injury my shoulder. Right before shooting the A-Roll, the parts with me on camera, I tripped. As I went to catch myself falling, I tore two of the muscles in my shoulder. It took about 6 weeks to completely heal. Yuck!

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