electrocub
New Member
I am building a charging circuit using the Max712. The thread is 12 Volt Gel Cell Charger. It requires a .62 ohm resistor which I don't have at the moment. I am going to order the correct resistor, but I also wanted to breadboard the circuit while I am waiting for the resistors. I got on the internet and found a parallel resistance calculator. Using the calculator, I discovered that I could use a one ohm and a two ohm resistor in parallel and come up with resistance of .66. Unfortunately, I didn't have a two ohm resistor, so I came up with the idea of putting two-1 ohm resistors in series then wrapping another one ohm resistor in parallel around the resistors in series. I figured this would be the equivalent of the resistance needed. I soldered the resistors together and it came out more like a triangle and when I put a ohm meter on it, the resistance came out as .9 ohms. If I put two one ohm resistors together, it comes out at .5 ohms which I think will be close enough for what I want to do.However, my question is , using Ohm's law, how do we calculate the circuit correctly at .9 instead of .66? the tolerance is 5%k but I don't think that is the issue. Thanks in advance.