Practical
Electronics
Volume 52. No. 4
April 2023
ISSN 2632 573X
Contents
Projects and Circuits
500W Power Amplifier – Part 1 by John Clarke
17
This large power amplifier produces big, clear sound with low noise and distortion. It
delivers 500W RMS into a 4Ω load and 270W into an 8Ω load.
Capacitor Discharge Welder – Part 2 by Phil Prosser
26
This Capacitor Discharge Welder has been carefully designed to deliver just the right
amount of weld energy. We described how it works last month, so now let’s make it!
Amplifier Clipping Indicator by John Clarke
38
This easy-to-build Amplifier Clipping Indicator is ideal for avoiding unpleasant sounds
and protecting your speakers; its LED shows even the briefest of clipping events.
Three low-noise HF-UHF Amplifiers by Jim Rowe
42
Useful overview of three low-cost HF-UHF amplifier modules offering 20dB of
gain over frequency ranges of 1MHz to 3GHz, 5MHz to 6GHz and 50MHz to 4GHz.
Series, Features and Columns
Techno Talk by Max The Magnificent
AI, Robots, Horticulture and Agriculture
8
The Fox Report by Barry Fox
Hopeless helplines and NASty problems
10
Net Work by Alan Winstanley
12
This month’s Net Work looks at the latest smart device protocol that promises ‘Plug
and Play’ simplicity, radio astronomer Frank Hyde and the ‘Queen of the Skies’.
Circuit Surgery by Ian Bell
Electronically controlled resistance – Part 8
46
Audio Out by Jake Rothman
Universal op amp board (optimised for audio electronics) – Part 3 (dual opamp/
adaptor version)
52
Max’s Cool Beans by Max The Magnificent
Arduino Bootcamp – Part 4
59
Wireless for the Warrior
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Classified ads and Advertiser index
Next month! – highlights of our next issue of Practical Electronics
2
4
6
7
7
Regulars and Services
Made in the UK.
9
16
51
68
71
72
Written in Britain, Australia,
the US and Ireland.
Read everywhere.
© Electron Publishing Limited 2023
Copyright in all drawings, photographs, articles,
technical designs, software and intellectual property
published in Practical Electronics is fully protected,
and reproduction or imitation in whole or in part are
expressly forbidden.
The May 2023 issue of Practical Electronics will be
published on Thursday, 6 April 2023 – see page 72.
Practical Electronics | April | 2023
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