Alt-BEAM Archive

Message #00382



To: Pete McCarthy dilbertpete@hotmail.com
From: "Jesse D." smokin@n-link.com
Date: Sun, 14 Feb 1999 10:43:00 -0600
Subject: [alt-beam] Re: determining current


Its called "Ohms Law" the most fundamental Equation in electronics

here it is

I=Current
E=Voltage
R=Resistance or Load
*=times, Multiply

Typically it is represented like this---- E
---
I*R
usually with a circle around it..

to find ANY of the values you just need to plug in the other 2

to find Voltage: E=I*R
to find resistance: R=E/I
to find CURRENT: I=E/R

so to find I (Current) you need to DIVIDE Voltage by Resistance

Now the tricky part is putting all the measurements in correct decimal
form

plug in resistance as OHMS so if you have a 3K Resistance across the
circuit use 3000

Plug in volts as millivolts (I think, been awhile since I did any
serious Ohms law math =] ) so if your reading 4.2 volts across the
power source WHEN IT IS HOOKED UP use 4200

divide 4200 by 3000

answer: 1.4

since you converted to millivolts and ohms, that milliamps or uA

so the current draw for this sample is 1.4uA



3K
|------------/\/\/\-----------|
| |
+ I=E/R |
I=1.4uA |
4.2v I = 4200uV |
------ |
- 3000ohms |
| |
|-----------------------------|


I may not be 100% correct on this so don't flame me =]

Go look it up on the WEB you will find better examples..


Pete McCarthy wrote:
>
> Hi List,
> I'm going to make this message as short as possible. Is there any way
> to determine how much current is in a circuit (from a circuit or a basic
> multimeter)
>
> ______________________________________________________
> Get Your Private, Free Email at http://www.hotmail.com

--
__ __ Jesse C. Druehl __ __
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