|
Farmall Tractors Discussion Board |
Why the disagreement on placement of resistor???
[ View Follow Ups ] [ Post Followup ] [ Return to Farmall Tractors Discussion Board ]
Posted by john d on September 01, 1999 at 18:27:44 from (206.141.74.34):
Don't want to be picking at a scab here, but several posts below were devoted to the proper placement of a ballast resistor in the ignition circuit of a tractor with a 12 volt battery and a 6 volt coil. I'm not understanding part of this, so if I've got it wrong, please help me out!! We all seem to be in agreement that the resistor is needed, and why it is needed. I remain confused on why there is supposed to be only one (1) clear place to install it, however. The primary circuit of the ignition system has electrons moving from the negative terminal on the battery through the switch, then to the coil, then the points, then ground. That's all there is to it. The condenser plays a role in producing a spark, but the current flow is: switch-to-coil-to points-to ground. If the resistor is between the switch and the coil, it reduces the voltage across the coil to something close to the 6 volts it was intended to have. BUT..... if the resistor is between the coil and the points, it's gonna do EXACTLY the same thing! It's a SERIES circuit, and that means there's only one path for the little electrons to travel. Putting the resistor between the coil and the points will NOT let the coil have 12 volts! Voltage is pressure, and the voltage drop across the coil will be the same, regardless of which side of it you mount the ballast resistor, as long as it's a series circuit. As a practical matter, you could mount the resistor between the battery and the switch and get the same results. It'll still work, and the coil will only receive approximately 6 volts. If I'm not understanding this correctly, help me out!
Follow Ups:
Post a Followup
|
