Where am I going wrong? Every way I do it I get 40/14.

 

hi,
Use the method as stated earlier, REDRAW as you go,
Try this as a procedure check.

Post your maths for each step.
E

 

Your work in post #17 is almost correct. You forgot to add R1 + R8.

 

Let's go back and do it step by step.

Step 1
R6 = R4 + R5 = 10 + 10 = 20

Step 2
R7 = R3//R6

1/R7 = 1/R3 + 1/R6 = 1/10 + 1/20 = (20 +10)/(10*20) = 30/200 = 3/20
R7 = 20/3

Step 3
R8 = R2 + R7 = 10 + 20/3 = (30 + 20)/3 = 50/3

Step 4
RT = R1//R8

1/RT = 1/R1 + 1/R8

I will leave it to you to calculate RT.

 

Ahhhh...thank you all for being patient with me. I found where I went wrong. Thank you Mr Chips.

 

For the TP:

Title: Understanding Basic Electronics, 1st Ed.
Publisher: The American Radio Relay League
ISBN: 0-87259-398-3