Using A Voltage Indicator With An 'under Load' Feature

[Schlitz]

Hello all electronics wizards. I'm looking for a way to get a little more out of my madvapes voltage indicator. As some of you know, this device screws into your atty connection, and also has a battery connector up top for testing your battery 'under load' with an atomizer attached.

So, for example, when I screw the indicator on a device with a 3.7 volt 14500 battery that has been fully charged, I will get a reading of 3.7-4.2 volts, as expected. When I throw on a 1.5 ohm atty, I get my voltage under load to read 3.3.

My question is this. How can I turn that 3.3 number into something that is useful to me. Is it possible to use this voltage indicator to test the ohms of my atty's? If so, what formula do I need to use in order to calculate the resistance of the atty attached? I've been racking my brain on this all morning, and I can't quite seem to wrap my head around it.

Thanks in advance for the help!

[Brian]

Not sure you can back into the ohms without knowing the power and/or amps.

However, if you know or atty is 1.5ohm, you can use the link below to plug in voltage under load of 3.3V and your atty resistance. Hit calculate and you get 7.2 watts of power and you're drawing 2.2 amps. I'm not really sure how all this works... there's an assumption that the battery can supply 2.2 amps. I reckon if the battery can't supply 2.2 amps, then you're not getting 7.2 watts. Maybe someone else and shed some light on that.

http://thelocust.net/ohm/

[mcquinn]

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.

Wow while I was looking for that I wasn't paying attention and my 901 drowned me.

Edited March 28, 2011 by mcquinn

[TomCatt]

Not sure if you can get the ohms of your arty with just the volts from the voltage indicator. The voltage indicator is just an easy way of getting volts under load without opening your batt/mod to get at the wiring. The simplest way to determine the ohms of the arty is to test with a multimeter.