If your single-chip system power is not large, directly use LM7805
If the power is relatively large, do not use LM7805. This is a series voltage regulator power module, which consumes a lot of power, heats up a lot and is easy to burn off. Then I suggest LM2576-5.0V, this is a switching voltage regulator power module, which is also very convenient to use. Just a few parts will do (LM2576, diode 1N5822, plus a 100uH inductor), this PSU has 5 pins, one is ON\/OFF pin, can control the off output. You can download the manual of LM2576 and use typical application circuit. If you have an email, I can send one to you.
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