ohms law formulas

[mcquinn]

Here is the variations on the ohms law formulas with which you can figure the amp draw or watts of your favorite atty by measuring the battery voltage and the atty element resistance .This is a theoretical value as things change when the temperature goes up or down or get wet or dry.

The unit of resistance is called Ohm in honor of a German scientice by the name of Georg Simon Ohm, who discovered that when a conductor has a resistance of 1 ohm then an emf of 1 volt will cause a current of 1 amp to flow through a conductor.
Ohms Law. I = E/R or R = E/I or E = IR.
DC. or Direct Current is one that the current always flows in one direction.
The letter for Current is I and is expressed in amperes.
The letter for voltage is E and is expressed in volts.
The letter for resistance is R and is expressed in ohms.
The letters for power or wattage are P and W and are expressed power and watts.
The formulas for ohms law are.
If you know R the resistance and E the voltage the formula for finding I current is I = E/R.
If you know E the voltage and I the current the formular for R resistance is R =E/I.
If you know I the current and R the resistance the formula for E voltage is E = IR.
If you know I the current and E the voltage the formula for P power or W watts is P =EI.
If you know W watts and I current the formula for E voltage is E = P/I.
If you know W Watts and E voltage the formula for I current is I = P/E.

[lordmage]

ah math run away.....

[mcquinn]

I keep postin stuff based on that, and I beleive I made a post that was incorrect due to faulty memory.So I posted this mostly for myself ,now if I could just remember where I put that post I would double check myself and if required call myself an idiot.

[lordmage]

you may have already been called an idiot of sorts i think fogie corrected you

[mcquinn]

Hey if that is the worse thing that happens to me today I will have it made.Besides that only people who don't do much never make mistakes.

[Royal]

Yep, you are correct mcquinn, Show me a person who never makes a mistake, and I will show you a person who never does anything.

If you ever need to have a post(s) edited, moved, merged or revised let lordmage or one of us know and we can take care of that for you.

[mcquinn]

ok, thanks, but I am fair game like anyone else.Besides that no one is perfect we can all learn and sometimes you have to get one of your dumb thoughts out for review or you may never know .That is one of the problems of only hanging with like minded people you can perpetuate a myth or worse .

[lordmage]

correcting post if an offer out to all members.

[mcquinn]

I cannot find the post but I am still having trouble with the math which is what caused me to work the formula wrong from memory.The premise was a 510 atty had 2.5 ohms of resistance at 5 volts that would be 2 amps of current draw and I think the 302 was supposed to be 3.7 ohms at 5 volts that would be close to 1 1/2 amps.I was for sure wrong with what I posted where ever it is .I need to measure the resistance of a few atty's and do it again.

[Royal]

mcquinn you are correct in your formula above, here is a handy tool to help to remember this.

The wheel above is divided into three sections:
Volts V (on top of the dividing line)
Amps (amperes) I (lower left below the dividing line)
Resistance R (lower right below the dividing line)
X represents the (multiply by sign)

To use the wheel, just cover the unknown quantity and what is left is the formula to find the unknown.
Example:
To find the current of a circuit (I), just cover the I or Amps section
and what remains is the V volts above the dividing line and the R ohms (resistance) below it. Now substitute the known values. Just divide the known volts by the known resistance.
Your answer will be the current in the circuit.
The same procedure is used to find the volts or resistance of a circuit!

I have some pictures I took while reading the resistance of a couple of 510 and pennstyle attys
using a calibrated/certified and ISO approved Fluke RMS multimeter. I will post them as soon as I load them into the computer. To give you a heads up, a new 510 atty that has been used for only about a week read 2.3 ohms. And a 510 atty that has been used for about 4 months read 2.5 ohms. Note: both of these attys have been only used on a 5 volt big battery mod, with routine atomizer cleaning. Yes you read right 2.5 ohms after 4 months of use. This is why I love the 510.