In this problem I'm trying to find the Thevenin resistance in the circuit below:
The first thing we do is remove all sources and the load resistor. So now we have the following circuit:
The part I'm stuck on is computing the total resistance between the load terminals a and b. If I remove R4, I can figure it out; R2, R7, and R8 all terminate at the ground node. We have R2 and R7 in parallel, which is in series with R5, which is in parallel with R8. Thinking of it this way, but then adding R4 into the mix, doesn't R4 begin and end at the same node?