As shown in figure, application scenario is 120 v AC, 60 hz, RV1 varistor, storm surge, red circle after the whole bridge rectifier circuit, please what do you use?
https://bbs.elecfans.com/data/attachment/forum/202102/03/131540ge3l3whrk9hreplk.png.thumb.jpg

CodePudding user response:

The red circle with two resistors
R1: role, eliminate the reverse voltage L1, OUT large current output and suddenly disconnected, L1 can produce high voltage, if no R1 loop will be released to circuit components damage,
R8: which CD1 charging current limiting resistor, when AC start charging, there is no electricity which CD1 (which CD1 should be a large capacitance), if there is no R8, this time FR1, L1, BD1, D1 produce very big electric current loop, such as serious when fusing FR1, damage BD1, D1, such as the original,