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Hands-On with B&K Precision 9140 Power Supply | Workbench Wednesdays #53

Bench power supplies are an essential piece of test equipment gear. And like most test gear, they have a wide range of capabilities. For example, the B&K Precision 9140 is a triple output supply that can output up to 300 watts. But, the basic capability isn’t what interested me about the supply. Instead, it was advanced features like rear panel triggers, adjustable slew rate, and built-in sequencing.

The element14 Community arranged for a B&K Precision 9140 power supply to be sent to me for a hands-on overview of those features.

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DIY Solder-In Oscilloscope Probes | Workbench Wednesdays #50

When you cannot get an oscilloscope probe into a tight spot, can you just use a piece of wire? Sometimes. When signal integrity matters, you CAN use a low-cost DIY solder-in probe. These probes attenuate the signal and use an oscilloscope’s high-bandwidth 50-ohm input. James shows how to build some solder-in probes when they work and when they do not work in this video.

Special thanks to Shabaz on the element14 community for the guide used here.

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Workbench Wednesdays

Spectrum Analyzer Basics | Workbench Wednesdays

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.

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Workbench Wednesdays

Tenma 72-2660 Portable Hand Held Supply | Workbench Wednesdays

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 injure 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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