Find and Eliminate Ground Loops

FIGURE 4: Ground isolator for three-prong powered appliances

Everything had been fine with my home entertainment center—comprising a TV, surround-sound amplifier, an AM/FM tuner, a ROKU, and a CD/DVD/BlueRay player—until I connected my desktop PC, which stores many of my music and video files on one of its … Continue reading






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How To Measure Temperature with a Soldering Iron

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Forget those expensive temperature sensors. Now you can use an ordinary heating element like a soldering iron to measure temperature. Daniel Maliks’s upgraded soldering iron will be a great addition to your workbench. In Circuit Cellar 191, Malik writes: There are many … Continue reading






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What Is Correlation?

Figure 1: This figure shows a given pattern (top) replicated two times in a noisy signal at different amplitudes (middle). The goal of the game is to identify the two replications (bottom).

Interested in learning about correlation and how to implement it in a digital signal processing system? In Circuit Cellar 299, Robert Lacoste addresses the subject without going overboard with complicated mathematics. He explains how a simple correlation calculation can drastically improve a system’s … Continue reading






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Utilize Simple Radios with Simple Computers

Photo 2: 315 MHz Transmitter and ATtiny85 CPU

I ordered some little UHF transmitters and receivers from suppliers on AliExpress, the Chinese equivalent of Amazon.com, in order to extend my door chimes into areas of my home where I could not hear them. These ridiculously inexpensive units are … Continue reading






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Translating Values: Number-to-ASCII Conversion (EE Tip #147)

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There is a neat trick for performing the number-to-ASCII conversion. (We are not sure of this trick’s origin. We’d love to hear from anyone who saw it long ago and can us more about it.) One starts by defining an … Continue reading






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Probe a Circuit with the Power Off (EE Tip #146)

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Imagine something is not working on your surface-mounted board, so you decide use your new oscilloscope. You take the probe scope in your right hand and put it on the microcontroller’s pin 23. Then, as you look at the scope’s … Continue reading






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Read Your Technical Documentation (EE Tip #145)

MCU

Last year we had a problem that showed up only after we started making the product in 1,000-piece runs. The problem was that some builds of the system took a very long time to power up. We had built about 10 prototypes, tested the design … Continue reading






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Impedance Matching Matters (EE Tip #145)

Figure 1: Impedance matching requirements must be anticipated. In particular, any embedded antenna will surely need manual matching for optimal performance. If you forget to include some area for a matching network like this one on your PCB, you won’t achieve the best performance.

RF designers, as well as more and more digital-oriented designers, are used to thinking about impedance matching. But it is very easy to forget it when you are designing a non-RF project. A non-matched circuit will generate power losses as well as nasty … Continue reading






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Liberally Apply Test Points (EE Tip #144)

MCU

When I first started designing, I did not understand the need for the scope posts for hardware test points. I could always tack on a wire or, with many through-hole parts, connect my scope right to the chip. But now test points are essential. … Continue reading






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Use Watchdog Timers (EE Tip #143)

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Watchdog timers are essential to many complete electronic system designs.  As Bob Japenga explains, following a few guidelines will help make your designs more effective. No longer used in just the realm of fault-tolerant systems, independent watchdog timers are put on systems … Continue reading






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Got Problematic Little Bits? (EE Tip #142)

Source: Raymond Vermeulen (Elektor, October 2011)

While testing a project, something strange happened (see the nearby image). The terminal showed nonsense, but the logic analyzer properly displayed “Elektor” in ASCII. The latter also indicated that the UART was operating at 4800 baud instead of the 19200 … Continue reading






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Troubleshoot Electronics Problems with Logging (EE Tip #141)

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Electrical engineers often develop “headless” electronic systems—that is, systems without user interfaces. And many of those systems are embedded within product and are generally out of reach when problems occur. Bob Japenga is an engineer with some advice about logging … Continue reading






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Diode Bridge Solution (EE Tip #140)

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Once I connected a battery up to a DSP in the wrong “direction,” thereby destroying the DSP. That incident drove home the necessity of “suspenders and belt” design. After the accident, my colleague and I added a diode to the … Continue reading






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Embedded Security (EE Tip #139)

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Embedded security is one of the most important topics in our industry. You could build an amazing microcontroller-based design, but if it is vulnerable to attack, it could become useless or even a liability.   Virginia Tech professor Patrick Schaumont … Continue reading






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Don’t Trust Connectors, Solder, or Wires (EE Tip #138)

Using the wrong pinout for a connector is a common error, especially on RS-232 ports where it’s approximately 50% probable that you’ll have the wrong RX/TX mapping. Swapping the rows of a connector (as you see here) is also quite common.

Engineer Robert Lacoste is one of our go-to resources for engineering tips and tricks. When we asked him for a few bits of general engineering advice, he responded with a list of more than 20 invaluable electrical engineering-related insights. One … Continue reading






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