Voltage Dividers

In an earlier section we brought up the topic of voltage dividers. A voltage divider can be a simple series circuit that divides up the supply voltage (potential) into one or more lower levels of voltage (potential).
In an earlier example we had a 9 volt battery and two series resistors.
In this section, we have a longer voltage divider. In the schematic drawing, Point A is the circuit common point. It is at some point mid way between the plus and minus terminals of the battery. This divider provides both positive voltage and negative voltage points within the same circuit. From Point A which in common, voltages at Point B and Point C will be more positive than Point A. Point D and Point E will be more negative to Point A.

 Given: 30 volt supply
 R1:  60 ohms
 R2:  60 ohms
 R3: 240 ohms
 R4: 100 ohms
 R5: 140 ohms

 Calculate the voltage, with respect to Point A for:
 Point B
 Point C
 Point D
 Point E

 Total series resistance is: (60+60+240+100+140) = 600 ohms
 Total series current is I = E / R  or ( 30 / 600 ) or 0.05 amps
 Point B = voltage across R2 and R3:  E = I X R
         work: E = ( 0.05 X 300 ) = 15 volts at Point B

 Point C = voltage across R3:  E = I X R
         work: E = ( 0.05 X 240 ) = 12 volts at Point C

 Point D = voltage across R4:  E = I X R (minus voltage)
         work: E = ( 0.05 X 100 ) = -5 volts at Point D

 Point E = voltage across R4 and R5:  E = I X R (minus voltage)
         work: E = ( 0.05 X 240 ) = -12 volts at Point E