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VCE Stuff => VCE Science => VCE Mathematics/Science/Technology => VCE Subjects + Help => VCE Physics => Topic started by: Ferdy270 on July 08, 2014, 01:15:50 pm

Title: Electronics - Voltage Dividers
Post by: Ferdy270 on July 08, 2014, 01:15:50 pm

Hi guys,

i was just wondering if anyone knows the correct transposed formulas for the voltage divider formula, it seems quite a blur since my friends have different formulas to myself.
Cheers  :D

Title: Re: Electronics - Voltage Dividers
Post by: Rod on July 08, 2014, 02:40:38 pm

I use this formula, works for me all the time:

Vout = Vin(R2/R1+R2)

A lot of my friends don't even use formulas, they do it in 10-15 seconds by looking at the ratios of each output voltage value. But that formula is pretty helpful as well if you're good at transposing.

Title: Re: Electronics - Voltage Dividers
Post by: PB on July 08, 2014, 05:02:37 pm

Yep, that's the right formula. And don't worry about people who can do those kind of calculations in their head. Its not necessarily the best indicator for success. Best to get into the habit of using formulas imo as it's safe and easily recognisable by examiners. Besides, it's great for worded questions too, a lot easier than trying to describe ratios in words :P

Title: Re: Electronics - Voltage Dividers
Post by: Stew_822 on July 08, 2014, 10:28:40 pm

I use Vx / Vin = Rx / Rt
Where Vx (usually called V_out)  is the voltage over Rx and Rt is the resistance of all the resistors, including RX

I also used Rx = (Vx * R_other) / (Vin - Vx)
To find the resistance of the resistor that Vout (which i call vx) is measured over
R_other is the resistance of the other resistors excluding Rx