Ok I'm new to dcc and need to build a test track. Book says to use a 20 ohm resistor But dont have a 20 ohm but I do have a 32 ohm can I use it instead???

i rightfully dont know about the tolerances of this resistance.. how many 32 ohm resistors do you have, because you could make a 20 ohm resistance with several 32 ohm resistors, well there aboutswith the tolerance level of the actual resistors..

In the electrical world as with the physical world, it you parallel 2 items, you in essense divide its resistance by 2.. 2 - 32 ohm resistors in parallel = 16 ohms 3 - 32 ohm resistors in parallel = 10.6 ohms and so on and so on Thats the way to do it.. once you achieve a tolerable level, you can add them together this scenario for 20 ohms you say, parallel 3 - 32 ohm resistors = 11ohms and add ( series) them to a another paralleled set of 3- 32 ohm resistors Roughly you will have 22 ohms thats how