Voltage divider confusion...

Thread Starter

Average Drinkability

Joined Mar 27, 2012
5
Directly from part of an assignment in my microcontrollers class: "...implement a voltage-divider circuit using 4 resisters [sic] (all with the same resistance) in series between +5V and ground. This circuit wil provide nodes with voltage levels of 3.75 V, 2.5 V, and 1.25 V..."

How is this even possible?? 3.75 + 2.5 + 1.25 is two and a half volts more than 5, not to mention 4 resistors of equal resistance in series will all have the same voltage... I only need to use the lower two anyway so I'd probably be better off ignoring this spec and building my own circuit.
 

DerStrom8

Joined Feb 20, 2011
2,390
Take a look at this:



The Vout is not the voltage drop across a single resistor, it is the voltage drop between the top connected resistor and ground. If you have the output set after the top resistor, it means you're adding the voltage drops of the bottom three, which is 3.75v. If you have it after the second, it means you're measuring the voltage drop across the bottom two resistors, and if you measure it right above the last resistor, you're only measuring the voltage drop across that last one.

Does this help, or should I draw a diagram related to your problem?

Regards,
Matt
 
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