EveryCircuit - Capacitive dropper 2mA

6 years ago

Attention do not read if you cant handel critique: Importante for this kind of circuits is an inrush current protecting/limiting resistor. In case you connect mains while its at its peak maximum voltage it will cause a very high peak current which might destroy your rectifier. With 500 Ω you are safe and it does not drop to much voltage dito power. Check this http://everycircuit.com/circuit/5871649359134720

kiani

6 years ago

Without a resistor suggested by Hurz, on no or light load even the output capacitor could cause a massive inrush current surge. Could it not?!

hurz

6 years ago

the big cap is the root cause for low impedance at inrush, right kiani, but this should be clear, you can even short it to demonstrate inrush

hurz

6 years ago

here the worst case screnario, the cap is charged with 325V you switch of in that moment, then you switch back on and do a jump of 650V http://everycircuit.com/circuit/4597789271785472 the cap can be seen as short in this inrush situation

kiani

6 years ago

Yes it should be clear.. . As a rule nothing is to assume,, as if you under estimate my ( someone's) intelligence you will be hurt and if you under estimate my stupidity then I will be hurt. Thus....assume = hurt.

hurz

6 years ago

i just emphasize the cap is the root, cuz you are talking about light load and EVEN the output cap can cause inrush. The load, one little LED can not cause this heavy inrush, its only the big cap, but even a 10uF cap will cause this problem

kiani

6 years ago

Yes my mis understanfing, cause in your first circuit yiu used dc, fir demo of switch on at peak and the massive current spike... Even only with the little capacitor..,, and i thought that this probkembexist in general anyway,, the lght load thing was just my confusion.. It is clear as water now.. Thank you.

hurz

6 years ago

the DC trick is just to stop the time, and to show whats happen if you are lucky abd catch the peak voltage of a sine wave