Searching for 12v switched power after ditching ballast and installing aftermarket electronic ignition
How it Works:
Use your finger on the citrcuit diagram to follow the path. Keep in mind the path does not end at the device. To be complete it goes back to the power source.
Current is electrons moving. No movement = no current, therefore zero amperes.
Voltage is an measure of electrons excited, looking to go somewhere. Voltage indicates potential energy available at that location being measured. It is a relative measurement. If the second lead is on ground, then its voltage above ground. If the second lead is another location in the circuit, then its a voltage difference between those two points.
Example
Imagine the engine is off. Turn on the headlights. The electrons flow through the headlight switch, and through to the headlights and then return to the battery negative. Ideally voltage stays the same all the way up to the headlight filament.
With nothing running a voltmeter only reveals where there is potential. It does not show whether the circuit leading to it can handle a load. A load causes flow when there is potential difference. More voltage results in higher flow. But when there is a small wire, or poor connections, these cause resistance to increasing flow.
When there is no flow, the voltage will be the same everywhere. So with everything off, the alternator stud, battery positive and all the wires in between should be at the same voltage (even if there are bad connections).
Analogy
Its just like pressure. If there is 12.8 psi on one end of a closed pipe, its 12.8 psi throught the pipe.It doesn't matter if inside the pipe there is a partial blockage. It's still 12.8 psi throughout.
If we could look inside, the pressure on both sides of the blockage would be 12.8.
Connecting that same pipe to an air gun or an impact wrench and lets see what happens to the pressure.
There's still 12.8 psi supplied, but on the other side of the restriction the pressure is lower. The more air being used downstream, the more the pressure drops.
So now you can study the wiring and circuit diagrams. Use your finger to follow the path from the alternator (power supply) to the various components.
Keep in mind the battery is special. When its charged, it draws no current. After starting, it needs recharge. The more it has been discharged, the more current it will initially draw upon recharge. An advantage of the '75 up wiring is the battery's needs are split off from the key switched circuits on the engine side of the firewall. But it does add more fusible links. Each of those can become restrictions if too much current is going through them.
How it Works:
Use your finger on the citrcuit diagram to follow the path. Keep in mind the path does not end at the device. To be complete it goes back to the power source.
Current is electrons moving. No movement = no current, therefore zero amperes.
Voltage is an measure of electrons excited, looking to go somewhere. Voltage indicates potential energy available at that location being measured. It is a relative measurement. If the second lead is on ground, then its voltage above ground. If the second lead is another location in the circuit, then its a voltage difference between those two points.
Example
Imagine the engine is off. Turn on the headlights. The electrons flow through the headlight switch, and through to the headlights and then return to the battery negative. Ideally voltage stays the same all the way up to the headlight filament.
With nothing running a voltmeter only reveals where there is potential. It does not show whether the circuit leading to it can handle a load. A load causes flow when there is potential difference. More voltage results in higher flow. But when there is a small wire, or poor connections, these cause resistance to increasing flow.
When there is no flow, the voltage will be the same everywhere. So with everything off, the alternator stud, battery positive and all the wires in between should be at the same voltage (even if there are bad connections).
Analogy
Its just like pressure. If there is 12.8 psi on one end of a closed pipe, its 12.8 psi throught the pipe.It doesn't matter if inside the pipe there is a partial blockage. It's still 12.8 psi throughout.
If we could look inside, the pressure on both sides of the blockage would be 12.8.
Connecting that same pipe to an air gun or an impact wrench and lets see what happens to the pressure.
There's still 12.8 psi supplied, but on the other side of the restriction the pressure is lower. The more air being used downstream, the more the pressure drops.
So now you can study the wiring and circuit diagrams. Use your finger to follow the path from the alternator (power supply) to the various components.
Keep in mind the battery is special. When its charged, it draws no current. After starting, it needs recharge. The more it has been discharged, the more current it will initially draw upon recharge. An advantage of the '75 up wiring is the battery's needs are split off from the key switched circuits on the engine side of the firewall. But it does add more fusible links. Each of those can become restrictions if too much current is going through them.