voltmeter and ammeter

[joyride]

whats the difference between the two?

[turtleEK1]

Voltmeter tests voltage. It needs to be parallel in a circuit.

Ammeter tests amp (current). It needs to be in series in a circuit.

:cool:

[dahon]

^^ what he said.
***voltmeter = voltage difference across a component, must be connected in parallel (ie with multimeter positive probe on one side, negative probe on other side)
*** ammeter = current flow (in AMPS), must be connected in series in a circuit (ie bridge a cut connection and it will check continuity/current reading of that connection - be sure to check your ammeter/multimeter fuse capacity (like 7.5A MAX) to make sure the current you are trying to read will not blow the meters fuse.)

[joyride]

whats more useful to have when you are running alot of auxillairies in your car?

[trism]

voltmeter, because each auxillary will draw a different amount of amps, but the cars overall voltage is constant

[absolutR]

physics yeh! lol

[joyride]

the more aux i run, the voltage can potentially decrease... is the fix a bigger alternator (to charge up the battery) or just get a bigger battery (so it doesnt drain as much)? am i thinking right or wong here?

[krogoth]

mm, im not sure how much of ur question i can answer, ill give it a shot anyway

if u get a new, bigger, better alternator, u wont be changing the voltage, ull be increasing the current being drawn from the engine, and thats how u get the battery charged up more quickly

im no expert when it comes to electronics, but i think that if all of ur components are connected to the same battery, then they will be configured in such a way to allow them to all recieve the maximum voltage of the battery

so theyr all wired in a parallel fashion

what changes as u add more components is the current available to them, as this current goes through more and more components, it will decrease

and u can increase the current available by using a new, better battery and/or better alternator, or u could use capacitors, which can be useful but are more of a quick fix imo

ur question about wat will be more useful to have depends on what u will be using the volt/ammeter on

tell us wat ur using it for and why, maybe we can answer ur question better that way

but generally, the current coming from the alternator is regulated, in a few different ways

if anything ive said is incorrect, please post with the correction

[trism]

that was a pretty overcomplicated answer for a simple question.


bascially, get a bigger battery, before you worry about getting a bigger alternator

[joyride]

rofl. i guess there was 2 questions i asked...

i was given both gauges for free, but i think i only need the voltmeter. i had no idea what the ammeter does... i'll be running additional aux with the same batt. the alternator is pretty weak so an upgrade is most likely req/d down the track.
thanks for the help so far OH crew :)

[dahon]

krogoths got the right answer and in no way is it overcomplicated. hes just explaining the basic jist of it.

oh u have a gauge for indicating battery strength?
i say just wire up the voltmeter, with positive connection to the positive terminal and ground to the battery preferably as the chassis may give you some resistance and give you a less than consistent reading. this will show you how much of a voltage drop you have in the battery indicating battery strength & when you should replace it.

connecting up an ammeter will not do you well really cos it will be connected in series to other components, and when those components are on it will be reading different values to if the components are off.
my old corolla GTi had a voltmeter to measure battery power, and thats basically all you need.

[dsp26]

I would get a high output alternator straight up considering how piss cheap they are these days. would rather do so in advance than find out 2 dead batteries later that it was the better investment.

not sure what car the OP has so heres an example.:
http://cgi.ebay.com/ebaymotors/HONDA-CIVIC-HIGH-OUTPUT-160-AMP-ALTERNATOR-89-95-CHROME_W0QQcmdZViewItemQQcategoryZ33573QQihZ023QQi temZ360056698135QQrdZ1QQsspagenameZWDVWQQtcZphoto

[krogoth]

^yeh, but no1 knows wat joyride wants to do.....

lol, wat u want a voltmeter or ammeter for?

maybe he just wants them for rice?? or maybe he wants to monitor votalge across something because hez worried its not getting enough power?

and maybe he wants to improve the current/voltage getting to the component and wondering wat the best way to do it would be?

[dsp26]

^yeh, but no1 knows wat joyride wants to do.....

lol, wat u want a voltmeter or ammeter for?

maybe he just wants them for rice?? or maybe he wants to monitor votalge across something because hez worried its not getting enough power?

and maybe he wants to improve the current/voltage getting to the component and wondering wat the best way to do it would be?

ooohhh....

lol

[beeza]

Get both hehehe

[trism]

an ammeter is no use, because you can only use it to measure the current draw of one thing, not of the entire electrical system like a voltmeter.

if you really wanted it, you could wire it to the alternator, to see how much current its pushing but thats about it

[joyride]

or maybe he wants to monitor votalge across something because hez worried its not getting enough power?

and maybe he wants to improve the current/voltage getting to the component and wondering wat the best way to do it would be?
both true

[trism]

well just wire the voltmeter to a 12v source, preferably one that is only 12v when ignition is on, otherwise you risk draining your battery

pos to pos, neg to ground

for the ammeter, what is it you want to measure the current of?