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Argus25 · 8th Sep 2019, 11:40 am

Usually, for most linear regulators a 0.1F 50V monolithic ceramic capacitor will do on the input and output directly to the ground pin of the regulator and if that is not ground you need the same bypass caps over that to to ground.

The minimum spec though for some regulators is 0.22 to 0.33uF. You cannot go wrong of course of you fit 1uF monolithic ceramic capacitors.

Some designs just use 2.2 or 4.7uF Tants, however the quality of these is variable and some have an unsuitably high ESR, especially 35V rated ones, which leads to regulator oscillation if they are the only bypass there.

8th Sep 2019, 11:40 am	#28
Argus25 No Longer a Member Join Date: Oct 2016 Location: Maroochydore, Queensland, Australia. Posts: 2,679	Re: Defective/ fake LM317T Usually, for most linear regulators a 0.1F 50V monolithic ceramic capacitor will do on the input and output directly to the ground pin of the regulator and if that is not ground you need the same bypass caps over that to to ground. The minimum spec though for some regulators is 0.22 to 0.33uF. You cannot go wrong of course of you fit 1uF monolithic ceramic capacitors. Some designs just use 2.2 or 4.7uF Tants, however the quality of these is variable and some have an unsuitably high ESR, especially 35V rated ones, which leads to regulator oscillation if they are the only bypass there.