Someone explain what I'm seeing on my Multimeter

[joeNuggetz]

I'm an electronics idiot, but I thought that if you have say a 1.2v batter and hook up leads from a multimeter to it, you would get a reading of 1.2v when its charged. How about if you use the car and drain the battery, shouldnt you see the volts go down or am I not understanding this.

Another thing, what is the mA setting on my meter showing me. The numbers are going all over the place. How can I read this info and use it?

[Nightwing]

Hum. If I get this wrong any one else can jump in and correct me. :) Wont mind one iota! :)

On a battery due to how it was constructed will be rated at a certain voltage and current. A fresh battery can be rated at 1.5v but may actualy have a potential of 1.7 or less when you hooked a meter across it with no load.

This next set of statement can even fry the mind of a first year electronic student.

All that voltage value list on the cell is how much pressure it has for its designed and chemical makeup. Same as you house water presure { around 30 to 60psi }. A carbon zinc battery, as you use it, drops voltage and if you plot it on a graph looks like a long slopping hill. Battries like Nicad are uses because they hold there voltage for most of the discharge cycle and drop like a rock near the end. You will see it drop a bit but for 1/2 the cycle is wont go down 1/2 or .75. Its only near the end that you see it drop off.

That is why I like the old analog meter to read current! They stablize what you see and what is occuring. Current or flow, like when you turn on a tap, depending on what is going on. With nothing running or idle will get one reading when running F or B will go up. When Turning will increase the current.

Wish Heathkit was around! They has a nice small cource on using voltmeters and other tools. :) Oh well progress. :(

So Voltage is like water presure and current is basically like water flow.

PS: Some circuits have about 10% wiggle room on measured values. So it may be designed for 1.2v after charge but you meter calibration, main power supply { AA bats } strength, last charge levels before this charge, componet tollerance etc will affect what it at and can change from this charge to the next.