Voltage Divider Rule question

Thread Starter

Xufyan

Joined Aug 3, 2010
114
Please look at the attached circuit ,

According to Voltage divider rule ,

V1 should be equals to,

10volts x (33k + 68k) / ( 33k + 68k + 100k ) = 5.02volts .

but the circuit says its 2.812 volts

and V2 equals to,

10volts x (68k) / ( 33k + 68k + 100k ) = 3.38volts .

but according to the circuit its 1.641 volts,
please explain where i am wrong :confused:
 

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t_n_k

Joined Mar 6, 2009
5,448
Current will flow in the two 47k resistors which will upset the divider relationship.
 

Tealc

Joined Jun 30, 2011
140
I'm completely new to this but simulating the initial divider circuit in Multisim with just the 100k, 33k and the 68k give the results you have calculated but as soon as I add in the 47k and additional 100k the voltage on my meters changed and when adding the op-amp in they changed again to the figures you found in your simulation.

As a guess I would say that for the bottom meter reading the 47k and 100k are working in parallel with the 68k to change the voltage divider values.
 
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