Capacitor as resistor

115

01:48:41

Can i use capacitor as "resistor"? When i use power resistor and 400v 1,2uf capacitor? Thanksfor answers.

published 6 years ago

PrathikP

6 years ago

Yes, you can. A capacitor when connected in an AC circuit behaves like a resistor, limiting current flow. Typical, capacitors are used in this manner in "capacitive dropper" power supplies. The advantage of using a capacitor for current limiting over a resistor is that a capacitor won't waste power (ideally; although a tiny amount power is lost in its tiny parasitic internal resistance). A resistor, on the other hand, would waste a huge amount of power and get very hot.

PrathikP

6 years ago

Using a capacitor dropper would mean a piss poor power factor, but since it is used for super low power power supplies, it's fine.

PrathikP

6 years ago

The reactance (it's effective resistance) can be calculated using the formula: Xc = 1/(2*pi*f*c)

giomix

6 years ago

But is dangerous, there is no galvanic isolation from mains to low voltage, so do not think to can touch a led pins. In EC capacitors start charged, but what happens in real in this circuit when t=0?

rich11292000

6 years ago

@Prathik Dont instruct material you have no knowledge on. This circuit draws 20 watts, and exceeds the capacitor voltage. Do not build.

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