Updated: Variable Power Supply using LM317 and 7805 ICs

Variable Power Supply using LM317 and 7805 ICs

I’ve updated this article to include a fan for heatsinking the voltage regulators. As originally built, you would be lucky to have 500mA of current delivery before the regulators went into thermal shutdown. A new schematic is included.


What happens when you exceed the power rating of a resistor?

Question: What happens when you exceed the power rating of a resistor?

This is a question that I asked myself while I was replacing a resistor in a battery charger. I calculated that the current would exceed the rating of the resistor, but I never saw smoke. So what really happens when you exceed the power rating of a resistor?

I used the scientific method on this project. I have my question, and now I need to form a hypothesis.
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