Electronics Basics


Chances are, you have used the continuity mode of your digital multimeter. But how much do you understand about how it works? In this video, we break down how the mode works, what the beep means, and show examples of how to use it (correctly.) It might seem silly to spend so much time on such a simple mode.

However, I have run across a few posts on the Internet, including the element14 Community where people do not understand continuity mode. Sometimes it is just a lack of experience and sometimes it is a total lack of understanding of what is happening. The biggest mistake, of course, is trying to measure continuity on a powered circuit. That is just a no-go. So in this video, I wanted to show what the meter is actually doing, how it sees different components, and give a couple of real-life examples of how to use it.

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.

See show notes on element14

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.

See show notes on element14

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.

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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