How do you go about finding the resistance from point A to B?

Question

http://img254.imageshack.us/img254/7421/elewe7.jpg I know the total resistance is between point A and B is 12 k but I don't understand how to simplify this circuit.

Answer 1

Simplify:
Ra=R1+R2+R3
Rb=(Ra×R4)÷(Ra+R4)
Rc=Rb+R5
Rd=R6+R7+R8
Re=R9+R10+R11
Rf=(Rd×Re)÷(Rd+Re)
Rt=Rc+Rf
Plugging knowns:
Ra=1+3.3+4.7=9
Rb=(9×18)÷27=6
Rc=6+1=7
Rd=1+2.2+6.8=10
Re=6.8+2.2+1=10
Rf=(10×10)÷20=5
Rt=7+5=12KΩ

Answer 2

Simplify the circuit in stages. Combine series resistances into a single value, then combine the simplified resistance values which are in parallel into a simplified value.

For example in your circuit there are 3 series Resistances in series (R6,R7,R8) which are in parallel with three other resistances (R,9,R10, R11) that are in series.

Add the resistance values of R6 + R7 + R8 = Rtotal1
Then add R9 + R10 + R11 = RTotal2

RTotal1 and RTotal2 are in parallel so compute the result
using product over sum for two parallel resistances

(Rtotal1 * RTotal2)/(Rtotal1 + RTotal2) = Requivalent

Repeat this process for the other sections of the circuit

Simplifiy smaller sections into a single value where possible adding series resistances and computing parallel resistances. As you do this you will see other ways to further simplify until you end up with a single resistance value which is the equivalent resistance of the entire circuit

Answer 3

wow this is kinda tricky
teh reason is bcuz they also put a resistor inbetween the first circuit and the second one,,, so i dont know whether to take the two diffeerent ciruist as being in paralell or in series

but from the paralell equation is couldnt be in parallel, so lets work with in series
so add R1+R2+R3+R4 from the first circuit as they are in series
and do the same
R6+R7+R8+R9+R10+R11
no R5 is what is causing a problem for me,,,
so lets assume that it is in series
then just add R5 to the totals above,,,

if this answer is incorrect then that means that circuits A and B are in series,,,,
good lluck
n get back to me n let me know how it works out