Exactly! You are getting it.. the LED is a diode.. which means its a semi-conductor and will always have a forward voltage drop.. IE, the amount of voltage neccessary to make the electronic gate close in the diode and thusly complete the circuit. The resistor has whatever voltage is left over from the forward voltage drop acros the LED. The resistor in this circuit, since the LED has 0 resistance, acts as a current limiter. The resistor value chosen, sets the maximum amount of current allowed to flow through the LED. A super conductor would allow for an unlimited amount of current....But super conductors are only found in those giant "Colliders" because they are two expensive to make and even then they aren't perfect.. (Super conductor is a device that can pass current through witout any loss whatsoever) An LED is a "semi-conductor" that can only handle a certain amount of current.
Ohms is a measure of resistance..Resistance can be used to guide the electrons of current where you want them to go. Thats also what the color code on the resistors means...but basically, we need to have 25 - 35 mA current. (miliamps) for the LED to light.. We don't measure the resistance across the LED because there should be zero resistance... thats what a semi-conductor is ... as close to a super conductor as you are going to get..
Watts is a measure of energy dissipation on the resistor..( A super conductor would have 0 watts of engery dissipation) You cant have a transfer of energy without some cost involved...in this case, the cost is heat disipation..
Now, if I have 2 resistors in series .. 12v --------- 220 Ohm ------- 320 Ohm ----- ground
I would add up the total resistance .. to get the total current... now once I have that I can then determine the exact voltage across each resistor...
In this case 220 + 320 = 540 Ohms
12 / 540 = .022 amps or 22 miliamps.. Now ( V = R * I) .. 220 * .022 = 4.8v
Standard Formula is V (Voltage), I (Current), R (Resistor),W (Watts)
V/I = R
V/R = I
I * R = V
Picures coming up ..
Ohms is a measure of resistance..Resistance can be used to guide the electrons of current where you want them to go. Thats also what the color code on the resistors means...but basically, we need to have 25 - 35 mA current. (miliamps) for the LED to light.. We don't measure the resistance across the LED because there should be zero resistance... thats what a semi-conductor is ... as close to a super conductor as you are going to get..
Watts is a measure of energy dissipation on the resistor..( A super conductor would have 0 watts of engery dissipation) You cant have a transfer of energy without some cost involved...in this case, the cost is heat disipation..
Now, if I have 2 resistors in series .. 12v --------- 220 Ohm ------- 320 Ohm ----- ground
I would add up the total resistance .. to get the total current... now once I have that I can then determine the exact voltage across each resistor...
In this case 220 + 320 = 540 Ohms
12 / 540 = .022 amps or 22 miliamps.. Now ( V = R * I) .. 220 * .022 = 4.8v
Standard Formula is V (Voltage), I (Current), R (Resistor),W (Watts)
V/I = R
V/R = I
I * R = V
Picures coming up ..
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