# Calculate current in a 120 VAC circuit with a series 10uF capacitor

• supak111
In summary, you made a circuit to desulfate lead acid batteries using a 120V AC mains source with no fuse and only a 10uF capacitor in series. If the capacitor shorts, you have an explosion of Battery Acid. Please put a 1Amp fuse in the circuit.
supak111
Hi can someone tell me please how much current is passed though below circuit:

120 AC 60Hz mains power going through a 10uF 500v capacitor in series

Calculate the reactance of the capacitor at 60 Hz, using X = 1/ 2 pi f C. Of course, get the units correct, C expressed in Farads.
Next just use "Ohms Law for AC" to find the current. I = V/X

supak111
supak111 said:
120 AC 60Hz mains power going through a 10uF 500v capacitor in series
You need to finish that sentence, or attach a circuit diagram.
Without knowing the impedance of the series load, the current computed will be a maximum.

dlgoff
Hi, maximum current was what I was after as I'm not yet sure what my load is going to be.

So capacitor impedance turn out is ~265 ohms, so my max current is ~0.45A (if I'm correct lol)

Thanks for the help

supak111 said:
Hi can someone tell me please how much current is passed though below circuit:

120 AC 60Hz mains power going through a 10uF 500v capacitor in series
supak111 said:
Hi, maximum current was what I was after as I'm not yet sure what my load is going to be.

So capacitor impedance turn out is ~265 ohms, so my max current is ~0.45A (if I'm correct lol)

Thanks for the help
Um, based on your past posting history at PF, this might indicate that you are considering another dangerous project. Have you gotten any training or enlisted the help of a local Mentor in your AC mains projects since your previous posts? Just looking out for you...

dlgoff and hutchphd
supak111 said:
Hi, maximum current was what I was after as I'm not yet sure what my load is going to be.

So capacitor impedance turn out is ~265 ohms, so my max current is ~0.45A (if I'm correct lol)

Thanks for the help
What are you trying to do ? This is a good resource..

It's a simple circuit I made (which actually works pretty damn good) to restore/desulfate old car lead acid batteries. I was just wondering what the max wattage the circuit was putting out.

OK

supak111 said:
It's a simple circuit I made (which actually works pretty damn good) to restore/desulfate old car lead acid batteries. I was just wondering what the max wattage the circuit was putting out.
You made a circuit to desulfate lead acid batteries using a 120V AC mains source with no fuse and only a 10uF capacitor in series...

berkeman said:
You made a circuit to desulfate lead acid batteries using a 120V AC mains source with no fuse and only a 10uF capacitor in series...
Fine... UNTIL THE CAPACITOR SHORTS! Then you have an explosion of Battery Acid.

Please put a 1Amp fuse in the circuit. Specifically a fuse, they are more reliable than a circuit breaker.

Have fun, but be safe,
Tom

No there is more to the circuit... obviously a full bridge rectifier and a few other things but its not a complicated circuit.

I do have a fuse, thanks

## 1. How do I calculate the current in a 120 VAC circuit with a series 10uF capacitor?

To calculate the current in a circuit with a series 10uF capacitor, you will need to use the formula I = V/Xc, where I is the current in amperes, V is the voltage in volts, and Xc is the capacitive reactance in ohms. In this case, Xc can be calculated using the formula Xc = 1/(2πfC), where f is the frequency in hertz and C is the capacitance in farads. Once you have calculated Xc, you can plug it into the first formula to find the current in the circuit.

## 2. What is the voltage in a 120 VAC circuit with a series 10uF capacitor?

The voltage in a circuit with a series 10uF capacitor is 120 volts. This is the standard voltage for alternating current (AC) circuits in most countries.

## 3. How does the 10uF capacitor affect the current in the circuit?

The 10uF capacitor affects the current in the circuit by creating a capacitive reactance, which is a type of resistance that is dependent on the frequency and capacitance in the circuit. This means that the current in the circuit will be lower than it would be without the capacitor present.

## 4. What happens to the current if the frequency in the circuit changes?

If the frequency in the circuit changes, the current will also change. This is because the capacitive reactance, which is a type of resistance created by the capacitor, is inversely proportional to the frequency. This means that as the frequency increases, the capacitive reactance decreases, and the current in the circuit will increase.

## 5. Can I use this formula to calculate the current in any circuit with a capacitor?

Yes, you can use this formula to calculate the current in any circuit with a capacitor as long as the circuit is in series and the voltage and frequency are known. However, it is important to note that this formula only applies to AC circuits, not DC circuits.

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