Archive for June, 2013

What’s the basic difference between a current feedback amplifier (CFA) and a voltage feedback amplifier (VFA)?

Simply put, in VFA the positive node Vp tracks the negative node Vn by action of negative feedback. In a CFA, however, the tracking happens by design.

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CFAs haven’t been around for as long as VFAs and are still less popular compared with their VFA counterparts, but they do offer great benefits when used in the right application.

Some key benefits of CFAs are their high bandwidth, extremely high slew rate and low distortion making them suitable for large transient interface including audio applications. Check out the LME49723 to appreciate the low noise and low distortion.  On the other hand, CFAs typically lack the precision of VFAs and can have large amounts of input bias currents which can result in a higher current noise density. They also have mismatched impedances at their inputs (low input impedance at the negative node) as a buffer is used internally between the inverting and non-inverting inputs.

Learn more about CFA’s and VFA’s here!

 

Happy Friday from BRL Test!

Happy Friday from BRL Test!

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A new study conducted by two researchers from Florida State University and the Swiss Federal Institute of Technology has found that the oil dispersants used following the Deepwater Horizon oil spill in 2010 may be causing oil to remain deposited in Gulf of Mexico beaches.

The researchers found that while oil dispersants quickly dissipated oil during the spill — the largest marine oil spill in history — the same chemicals may be causing oil to remain deposited deep in Gulf of Mexico beaches.  The study noted that oil mixed with dispersants more easily enters sandy sediment, where it can penetrate deeper and last longer than untreated oil.

The researchers tested the ability of oil to penetrate into sand with and without dispersants, with the help of an Agilent gas chromatograph coupled to a mass spectrometer.

For more information on this topic – click here.

CNN Political Ticker

Washington (CNN) — The Supreme Court has dismissed a closely-watched appeal over same-sex marriage on jurisdictional grounds, ruling Wednesday private parties do not have “standing” to defend California’s voter-approved ballot measure barring gay and lesbians couples from state-sanctioned wedlock.

The ruling permits same-sex couples in California to legally marry.

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Happy Wednesday!

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Happy Birthday Tracy!

Click here to see video on BRLtest.com, request a free quote, and check out specs!

Click here to see video on BRLtest.com, request a free quote, and check out specs!

In stock and for sale — Agilent N9340B Spectrum Analyzer! Price includes full warranty and calibration, guaranteed to work right out of the box. Backed by the industry’s top technicians! Call (866) 275-8378 or click here to buy today!

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In stock and for sale – brand new Picotest G5100A Arbitrary Waveform Generator! Price includes full warranty and calibration, guaranteed to work right out of the box. Backed by the industry’s top technicians! Call (866) 275-878 or click here to buy!

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Check out this tutorial from Agilent Technologies, which describes how Agilent DMMs make 4 wire ohm measurements. Additionally, it shows how to make a 4 wire ohm measurement with the 34410A DMM.

How to use the 4 wire ohm function for Agilent DMMs

Need a multimeter like the one featured in the tutorial?

Request a quote on any model and make here.

Texas Instruments: Engineer It – How to do precision current limiting for a supercapacitor application

Learn how to limit the charging current of a supercapacitor. Texas Instruments (TI) applications engineer Amy Le walks you through the block diagram, provides sample calculations, and demonstrates how to precisely limit the output current of a switching regulator.