# Variable AC OUTPUT VOLTAGE

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##### New Member
How can AC voltage be doubled or tripled using 120v/220v transformer ? Thanks

#### ChristianCMcKay

##### New Member
Okay, this is my attempt at this, and it's the first time and it's been a while since I've taken AC circuits, but here's my go.

View attachment 68563

In the chatroom, we were working on a 1:2 voltage output. To do this, we will select a value inductor to use to find a starting point. We'll use a 1 uH inductor just for this example.
The signal was going to be 1 Volt @ 60 Hz.

The voltage across the inductor will have to be 2 volts, and just for simplicity, the voltage across the capacitor will be 1 volt. This will provide a point where the voltage is a ratio of 1:2 and 1:3. This means the altered version of this circuit will look like this.

View attachment 68564

So voltage across both the capacitor and the inductor will be 3 volts, and the voltage across just the inductor will be 2 volts, with a 1 uH inductor. To find the inductive reactance of the inductor use the following formula:

[LATEX]X_{L} = \frac{1}{2\pi*60Hz*1uH}[/LATEX]

The next step will be to get the ratio of voltage across the inductor versus the whole circuit.

[LATEX]\frac{V_{L}}{V_{CL}} = \frac{X_{L}}{X_{L}+X_{C}} = \frac{2}{3}[/LATEX]

To solve for the capacitive reactance, we can manipulate this formula to say

[LATEX]X_{C} = \frac{X_{L}(V_{CL}-V_{L})}{V_{L}}[/LATEX]

And once you some for the capacitive reactance, you can find the capacitance using the formula

[LATEX]C = \frac{1}{2\pi*60*X_{C}}[/LATEX]

Disclaimer: It's 5 in the morning and I have been awake for hours. It's entirely possible I've done this wrong, and if I have, I'll correct it and try again tomorrow.

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#### MrAl

##### Well-Known Member
How can AC voltage be doubled or tripled using 120v/220v transformer ? Thanks
Hi,

Do you want AC output or DC output?

Whichever you want, we need to know the power output level too...1 watt, 10 watts, 100 watts, 1000 watts?

In some cases the best way is just to use a transformer with the correct turns ratio.

#### ChristianCMcKay

##### New Member
I was in the chat when he asked for help. All he needs the output voltage doubled or tripled, but it has to still be an AC output. No power specifications.

#### 4pyros

##### Well-Known Member
How can AC voltage be doubled or tripled using 120v/220v transformer ? Thanks
Do you want it variable or fixed???

##### New Member
They told me that it must be a variable type. the power i guess is 50 watts.
Sir i have done here a schematic diagram of a power supply. do you think anything is wrong in my work.
uhmm don't mind the specifications that i put. it's wrong. if you have any suggestions in my work please do.
thanks.

#### MrAl

##### Well-Known Member
Hi,

That looks like you are trying to build a DC power supply. So to start, where are your rectifier diodes?

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