Red positive black negative12/18/2023 ![]() If there are a long list of numbers in your worksheet, now, you want to format the negative values as red font and positive numbers ad green font for viewing them easier. Having switches ground a circuit in an automobile may be slightly better for the longevity of the switch contacts (very slightly), but with all circuits ending at the battery terminals, it’s like trying to notice the flush of one toilet at the end of the sewer line, assuming accessories in the car have been left on.Īs (hopefully) you know, the reason for making the last connection the negative one, is the vehicle’s chassis being connected to the negative pole of the battery, so there’s less danger of slipping and making a really impressive spark should the chassis be contacted with the positive cable, and ensuring that the last connection to be made is far from the battery.How to format the cell value red if negative and green if positive in Excel? The only difference is which way the current will be flowing for the surge, and thus which direction the spark will spray. For that matter, if you have a coil connected to a battery, it hardly matters which side you disconnect–the field will still collapse and you will get just as much of a surge from the stored energy. ![]() If you can tell the difference, you are blessed with far better perception than I have. Try it–you will get just as big a spark whatever connection you decide to make last. We’re not talking a pole transformer fed by a HV line here. While you may be technically right, when you’re dealing with 12 volts, and at the battery, not at the end of any one circuit, any difference in potential is going to be negligible at best. I’ll admit that I’ve made the last connection to a battery terminal before when jumping a car and not being able to find a good connection on the body, but it’s still not the right way to do I also have studied electronics. Still the odds are in your favor, but it’s still a good idea to make the last connection away from the battery, and turn your face away from the battery when doing it. On a hot summer day with the air kind of still, it’s a little worse. The danger of blowing up a battery is pretty minimal on a cold day, outdoors, with the hood open and the wind blowing, and the last connection made on the dead battery. Typically when jumping a car, I wiggle the last connection around on the ground point, hoping to see a spark, because that means I’ve got a good connection and the dead battery is likely charging. And if your hands are steady when you make that last connection, you may not even see a spark–the spark occurs when the connection is made and then broken, such as when trying to establish a connection on a painted, dirty, or somewhat corroded piece of metal. ![]() The only slight difference on a DC circuit may be the direction that the spark ‘sprays’ when you make that connection. You might get a bigger spark if you’re breaking the circuit on an inductive load that stores EMF, such as a motor, relay coil, solenoid, or ignition coil, but that doesn’t really apply either for the purposes of jump starting a vehicle. ![]() And if the circuit is broken at either end, you should see the same potential between the points that complete the circuit when measuring with a voltmeter. The electricity doesn’t get ‘tired’ after going through the load–you can measure current at either end of the circuit and it will be the same. You will still get a spark on the last connection you make when you complete the circuit. JayWB, it doesn’t matter in the slightest what side of the circuit is switched for the purposes of jump starting a vehicle.
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