So after a 27+ response thread which didn't really do much to further my grasp of the concepts, I decided to really tackle the basics.

Example:

Assuming I've got a 12V power supply and I'd like to power an LED with 5V at 25mA. I know that I take the initial voltage (12V), subtract the desired final voltage (5V) and now I know that I need to get rid of 7V while restricting the current to 25mA.

Using Ohms' Law I *know* that I have to divide 7V by the desired current (25mA) which tells me to use a 280Ω resistor. I know that if I plug this resistor into my circuit, that the resistor will [have a voltage] drop [of] 7V and restrict my current to the desired 25mA.

What I don't understand is WHY or HOW this is happening - eg. the actual *mechanism* behind this, and

I'm trying to wrap my head around this one concept - "voltage drop across a resistor". While probably simple in this example, I don't understand why - in a simple series circuit - 'any' resistor drops 100% of 'any' voltage in 'any' circuit. (so far I've played around with a breadboard, and 5-12V, and this is what I've observed)

Another example, if we forget the LED for a moment, I place a single resistor between the terminals of a battery, the resulting voltage drop across the resistor (I'm assuming that "voltage drop across a resistor" means voltage 'consumed/neutralized' by the resistor) is near 100%, while if I place an LED into that circuit, all of a sudden the 'voltage drop' is 'shared'. Why does it work this way? How can this be calculated/anticipated? What am I missing?

It's baffling! Ughh...

I really appreciate the input I've had from many of the good and knowledgable folks on here, however I want to state in advance that I'm not simply looking for "the answer". Rather, I'd like to understand the fundamental mechanics of the circuit. I say that because I appreciate your time/input and I'd like to be clear on *specifically* the type of response I'm looking for so as not to waste it.

If others might benefit from technical, short, scientific answers to this question, then by all means - post away. I however will not, and as such, I wanted to clarify specifically what type of explanation I'd like to have.

This place is really terrific and I'm glad I came across it. I am certainly doing LOADS of reading on my own and hopefully, these concepts will come together in my brain at some point in the not-so-distant future.

Example:

Assuming I've got a 12V power supply and I'd like to power an LED with 5V at 25mA. I know that I take the initial voltage (12V), subtract the desired final voltage (5V) and now I know that I need to get rid of 7V while restricting the current to 25mA.

Using Ohms' Law I *know* that I have to divide 7V by the desired current (25mA) which tells me to use a 280Ω resistor. I know that if I plug this resistor into my circuit, that the resistor will [have a voltage] drop [of] 7V and restrict my current to the desired 25mA.

What I don't understand is WHY or HOW this is happening - eg. the actual *mechanism* behind this, and

__I'd like someone to explain this to me, step by step, on a 4-year-old, 'draw-me-a-picture', level__.I'm trying to wrap my head around this one concept - "voltage drop across a resistor". While probably simple in this example, I don't understand why - in a simple series circuit - 'any' resistor drops 100% of 'any' voltage in 'any' circuit. (so far I've played around with a breadboard, and 5-12V, and this is what I've observed)

Another example, if we forget the LED for a moment, I place a single resistor between the terminals of a battery, the resulting voltage drop across the resistor (I'm assuming that "voltage drop across a resistor" means voltage 'consumed/neutralized' by the resistor) is near 100%, while if I place an LED into that circuit, all of a sudden the 'voltage drop' is 'shared'. Why does it work this way? How can this be calculated/anticipated? What am I missing?

It's baffling! Ughh...

I really appreciate the input I've had from many of the good and knowledgable folks on here, however I want to state in advance that I'm not simply looking for "the answer". Rather, I'd like to understand the fundamental mechanics of the circuit. I say that because I appreciate your time/input and I'd like to be clear on *specifically* the type of response I'm looking for so as not to waste it.

If others might benefit from technical, short, scientific answers to this question, then by all means - post away. I however will not, and as such, I wanted to clarify specifically what type of explanation I'd like to have.

This place is really terrific and I'm glad I came across it. I am certainly doing LOADS of reading on my own and hopefully, these concepts will come together in my brain at some point in the not-so-distant future.

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