I had ordered a linear power supply for a WSPR receiver I am building. The "standard" power supplies used in the last 20 years are based on high-speed switching. This allows much smaller transformers, lighter weight and greater efficiencies. The only problem is that if they are not shielded well, they can emit a lot of radio interference right where I am trying to listen. I will be trying to hear stations several thousand miles distant that are transmitting with less than one watt radiated power. When doing this, you try to minimize all potential noise sources.
My supply came in today - took a look at it and it used a 723 integrated circuit voltage regulator chip with a 2N3055 power transister for the output stage. Talk about a walk down memory lane:
RCA first marketed the 2N3055 in the 1960's
2N3055
The 2N3055 is a silicon NPN power transistor intended for general purpose applications. It was introduced in the early 1960s by RCA using a hometaxial power transistor process, transitioned to an epitaxial base in the mid-1970s. Its numbering follows the JEDEC standard. It is a transistor type of enduring popularity.
Enduring popularity - no shit Sherlock... The 723 is just as venerable:
Bob Widlar
Robert John (Bob) Widlar (pronounced wide-lar; November 30, 1937 – February 27, 1991) was an American electrical engineer and a pioneering designer of linear integrated circuits (ICs). Widlar invented the basic building blocks of linear ICs including the Widlar current source, the Widlar bandgap voltage reference and the Widlar output stage. From 1964 to 1970, Widlar, together with David Talbert, created the first mass-produced operational amplifier ICs (μA702, μA709), the first integrated voltage regulator ICs µA723 by Fairchild launched in 1967
Nothing wrong at all with these component choices - fun to see that chips I grew up with are still in current production and are still suitable for the task.
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