The output of a certain voltage divider is 12 V with no load. When a load is connected, does the output voltage decrease?

1 Answer
Jul 26, 2018

Answer:

Yes

Explanation:

The voltage at the output of the voltage divider is determined by the voltage dropped across the resistors in the divider.

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[image source: https://www.allaboutcircuits.com/tools/voltage-divider-calculator/ ]

With no load, the current flowing in #R_1# is

#I_(R_1) = V_("in")/(R_1+R_2) " "(= I_(R_2))#

If a load (#R_L#) is connected to the output, (across #R_2#) the resistance at the output decreases from #R_2#, to #R_2# in parallel with #R_L#.

So #I_(R_(1_L)) = V_("in")/(R_1+(R_2|\|R_L)#

#(R_2|\|R_L) < R_2 ", so " I_(R_(1_L)) > I_(R_1)#

So we see that the current through #R_1# increases when a load is connected.

The voltage dropped across #R_1# therefore increases, so the voltage at the output decreases.