[KB6NU] From the trade magazines: Automatic impedance matching, AC grounding, rechargeable batteries
 

KB6NU's Ham Radio Blog

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From the trade magazines: Automatic impedance matching, AC grounding,
rechargeable batteries

Posted: 02 Jun 2021 08:36 AM PDT
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Automatic impedance matching in RF design

Impedance (Z) matching is an essential part of most RF circuit design.
Regardless of what you’re designing, getting as much power to a load is a
top target. Impedances must be matched to transfer the maximum amount of
signal power between stages. And in power amplifiers (PAs), impedance
matching is critical to getting the maximum power to the final load and
maintaining PA linearity. Impedance matching to an antenna in a receiver or
transmitter is an essential process.

Some loads are constant; thus, a single fixed Z-matching circuit can be
used. But in other applications, that final load may change, or the
frequency of operation will change, meaning that a fixed Z-match circuit
will not produce the desired results. For these applications, a variable
matching network that you can adjust is needed. Better still is a variable
and automatic Z-match circuit that adjusts itself to the immediate load or
frequency conditions.

Auto Z matching is more common than you think. If you own a recent
smartphone, you’re probably using an auto Z-match antenna tuner. However,
there are other applications. Here’s a primer on this topic for your
elucidation and cogitation.
read more

AC grounding: essential, dangerous, or both?

Most electrical engineers learn early-on about the importance of what are
referred to as circuit grounds. In many cases, whatever your problem,
adding a ground or improving the one you have (meaning lower impedance) is
a good thing that can’t hurt. That’s what circuit EEs have drilled into
them as they work and debug bench circuits prototypes, and more, and learn
to connect the analog ground to the digital ground at one point only to
minimize unwanted ground-current flow and associated noise.

In most cases, such grounding does improve circuit performance, but as
every experienced engineer knows, every rule has legitimate exceptions, and
grounding is one of them. A large part of the confusion comes from the
ambiguous and this sloppy terminology associated with that
innocent-sounding seven-letter word.
read more

Rechargeable batteries enable greener electronics

While batteries provide untethered power, enabling convenience,
dependability, and mobility, environmental responsibility suggests that
rechargeable batteries have the same benefits, but can save money while
reducing the amount of waste. This article examines the benefits offered by
rechargeable battery technology, enabling us to make life better.
read more

The post From the trade magazines: Automatic impedance matching, AC
grounding, rechargeable batteries appeared first on KB6NUs Ham Radio Blog.