The power supply circuit has a simple design, but it is a useful circuit that you can use in various circuit tests using 2 LM317T Positive regulators and 2 LM337T Negative voltage regulators. The output voltage can be adjusted gradually with the commutator. In fact, the voltage range can be adjusted more precisely with the potentiometer, but this type of commutator works in designs.
Symmetrical Power Supply Circuit Diagram
Source: http://www.siliconchip.com.au/cms/A_30603/article.html
Simple Symmetric Power Supply Circuit with LM317T LM337T PCB schematic alternative link:
Simple Symmetric Power Supply Circuit with LM317T LM337T
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Published: 2008/09/04 Tags: power electronic projects, power supply circuit, power supply project
Speaker Protection and Fan Control Circuit
This loudspeaker and fan controller has been specifically designed to suit the Ultra-LD 100W per channel amplifier described in the March and May 2000 issues. Not only does it provide muting at switch-on and switch-off to prevent any thumps from the loudspeakers, it also protects the loudspeakers against catastrophic failure in the amplifier. In addition, it provides temperature control for the fan-cooled heatsink, switching the fan on if the heatsink temperature rises above 60°C.
Speaker Protection Fan Control