How do I know if my ignition coil has an internal resistor?

Using an ohmmeter, check the resistance between the side terminals of the coil. Do this with all of the wires to the coil disconnected. You should see 0.75 to 0.81 ohm of resistance. Then check the resistance between either side terminal and the center high tension terminal.

What does an internal resistor do?

The higher the internal resistor, the lower the battery voltage. During active mode, when the highest current level is drawn from the battery, this voltage drop will be at its maximum. Therefore, the battery voltage, while being discharged at high current, can be a simple indicator of the battery’s remaining capacity.

What does a resistor do on a ignition coil?

In simple terms, the ballast resistor in a Mopar limits the amperage, or current flow, through the coil while the engine is running, thereby extending the life of the coil and breaker points of the distributor.

Do you need a resistor with a 12 volt coil?

If a 6 volt ignition system is converted to 12 volts and a Delco style 12 volt coil with an internal resistor is installed as part of the conversion, no external resistors are required. The 12 volt battery must be connected so the negative (-) battery terminal is connected to ground.

How do you check the resistance of a coil?

Resistance can be measured with a Multimeter.

1. Set the multimeter to measure resistance (ohms).
2. Connect the positive lead to the positive terminal of the coil.
3. Connect the negative lead to the negative terminal.
4. A typical value would read 0.4 – 2 ohms.

What is the resistance of an ignition coil?

Most ignition coils should have a primary resistance falling somewhere between 0.4 and 2 ohms; however, refer to your manufacturer’s specifications for the correct reading. If a reading of zero is displayed, that signifies that the ignition coil has shorted internally in the primary windings and needs to be replaced.

Do resistors reduce voltage?

Voltage varies directly with current. “R” is the constant of proportionality telling how much it varies. If I add in a resistor to a circuit, the voltage decreases. If you have a resistor in a circuit, with a current flowing through it, there will be a voltage dropped across the resistor (as given by Ohm’s law).

Do resistors change voltage?

Voltage applied to a series circuit is equal to the sum of the individual voltage drops. The voltage drop across a resistor in a series circuit is directly proportional to the size of the resistor. If the circuit is broken at any point, no current will flow.

What happens if you don’t use a ballast resistor?

If the ballast resistor is not working properly, the vehicle will not start. Since it is an electrical system, it is something best left to the professionals to handle. The only way to have the vehicle up and running again is with a ballast resistor replacement.

Does a resistor reduce voltage?

If a component in your circuit requires less voltage than the rest of your circuit, a resistor will create a voltage drop to ensure the component does not receive too much voltage. The resistor will create a voltage drop by slowing down, or resisting, the electrons as they try to flow through the resistor.

What does the ignition coil resistor do?

That regulating device is the ignition coil resistor. The resistor acts as a regulator, allowing adequate current to flow to the ignition coil to provide a good spark while the starter is engaged and limit the amount of current flowing to the coil once the engine starts.

What is a coil ballast resistor?

A Ballast Resistor is an extra electrical “load” which is installed in the electric circuit providing power to the ignition coil for the purpose of reducing the voltage that the coil receives. This may seem somewhat counter-intuitive as one would think that the higher the voltage to the coil,…

What is an ignition resistor?

Ballast resistors in your automobile are devices designed to limit the amount of electric current in a circuit. This component is also referred to as an ignition ballast resistor or ignition coil resistor. It is typically utilized in older automobiles.