Electricity and how it works.

After reading several threads over the course of time regarding lighting, stereo installs and the like; I hope that this will give you a better understanding of how electricity works, so that your installations are of sufficient capacity so things don't go wrong.


This will be dumbed down for some who read this. I'm writing as if you know nothing.


Without further ado...

Ohm's law states:

The current flowing through a circuit is equal to the voltage applied to the circuit divided by the resistance of the circuit.

Draw this on a piece of paper, it'll make this easier to follow: draw a circle with a horizontal line in the middle to make 2 halves and draw a vertical line in the bottom half.
In the top write: E (P) volts (watts)
In the bottom left: I (I) current (current) Bottom right: R (E) resistance (volts)

This is the Ohm's law wheel with watts laws in parentheses ( ). Cover what you're looking for and what's left is the formula to find it.

 

Series circuits:
With a series circuit, the loads are connected end to end with 2 leads to connect to the source. Side note: Dropping batteries into a flashlight is also a series circuit.


In this circuit, all the current flows through each load, and each load will have a voltage drop across it and those will add up to the source voltage. For example, we have 10-10 ohm resistors connected in series. Resistance in series is cumulative, so adding up the resistors tells us we have a 100 ohms. Now, let's apply 100 volts. How much current will flow through the circuit? Cover "I" on the wheel, and the formula is E/R. 100 volts/100 ohms= 1amp. That 1 amp is flowing through each of the resistors. Now we can find the voltage drop across each resistor. We know that 1 amp of current is flowing in this circuit and that we have 10 ohm resistors. Covering E on the wheel shows us the the formula IxR, current x resistance=10 volts.


Knowing this, we can determine the wattage necessary to dissipate the heat it's going to generate without blowing up.

Using the wheel and the letters in parentheses, cover P. The formula IxE= 10 watts.

 

Next, let's move on to parallel circuits. Instead of connecting our resistors end to end, we'll connect all the leads from each side together. In this scenario, the voltage across each resistor is the same and the current will divide up amongst the resistors. There are several formulas for determining total resistance in a parallel circuits. If all the resistors are the same value, divide the value by the number of resistors. If they are different values then use the formula, 1/ 1/R1+1/R2+1/R3… to calculate total resistance. Using the same 10-10 ohm resistors, connected in parallel gives us a total resistance of 1 ohm. Using the wheel, we determine that the total current in this circuit with the same 100 volts applied used 100 amps of current!

Each resistor will carry 10 amps of current using the formula I=E/R. Determining the wattage, P=IxE, we see that 1000 watt resistors are needed to accommodate that load on each resistor.

Resistors in parallel will always have a total resistance LESS than the lowest value resistor


Voltage and current are inversely proportional. Higher voltage , lower current and vise versa. Because a watt is a watt is a watt… 100 watts with 100 volts is only 1 amp of current, whereas 100 watts with 10 volts is 10 amps of current.


Now we have 5 lights with different wattages that we want to turn on with a single switch. 2- 50 watt lights, 2-20 watt lights and a 5 watt light. A total of 145 watts. How big of a fuse is needed? How much current does the switch need to carry? What size wire will carry that load without overheating and damaging the insulation? We'll use 12 volts this time for our calculations. Cover the I and our formula, P/E= 12.083 amps. For safety, and to avoid nuisance been fuses, always round up. We need at least 13 amp fuse and switch for these lights.

 

You lost me at "After"

 

When you unplug an appliance, why doesn't the electricity just fall out of the outlet? What's holding it in?






again.....

 

It's easy once it clicks. That's me on the right up there. Lol. If I can do it so can you

 

Witchcraft

 

*Important note*

If you're dealing with cheap Chinese LED lighting, the black wire is positive and the white wire is negative.

 

reported.

 

Reported for reporting him.

 

They are suppose to be backwards it's Chinese

 

An Indian saw an Eagle over a Rock...

 

Let'VVvmVCvZv,

Air. Electricity is lazy. It wants the path of least resistance. High voltages will jump the store Gap if you're close enough.

 

thanks.....