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Bingos Weekly Lesson "Volt Meters"
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Author:  Bingo [ Mon Dec 06, 2004 7:40 am ]
Post subject:  Bingos Weekly Lesson "Volt Meters"

Bingo’s weekly lesson.
Please read this post first http://4g61t.org/phpBB2/viewtopic.php?t=11634

Basic Electricity 2
Voltmeters

Ahh the almighty voltmeter. The single most important tool. I wont spend much time explaining all of the individual tests (you can search that on your own). Instead I will simply explain how to use the tool. If there are any specific questions about doing a test please post it. Enjoy!

Volt Potential tests.
Basically this is to test how much potential a circuit has. For example, test your batt voltage. In this test, place your meter to volts then place the positive lead to the positive on the batt and same for the negative lead and negative batt post. You should read somewhere in the area of 12.6 volts. This is the potential voltage your batt has. Now to do a voltage reading somewhere in a circuit other than the batt. What you would do is place the + lead in the circuit and the – to the body or a known good ground. This reading is the voltage at that point. Now to do a voltage drop test. Take the + lead and place it before a consumer and take the – lead and place it after the consumer. This is the voltage that the consumer is consuming. The voltage drop test can also be done to test a wire for excessive resistance.

Resistance tests.
This test is used to find resistance in a circuit that is to little or to much
(out of spec). In this test you will disconnect the power from the consumer (remove the + and – supplies to the consumer.) Take your meter and switch it to The ohm’s horse shoe symbol. Take the + lead and place it on one side of the consumer and take the – lead and place it on the other. The meter will send a small voltage and then measure it when it is received through the other side. In turn this will calculate known resistance. Also like the voltage test you can also use this to measure a wires condition.

Amp / Current flow test.
In this test you can blow your meters fuse so only do it to simple circuits. NO HEADLIGHT CURCUITS. Place your meter to either the high or low amp settings and change the + lead to the correct port on the meter. Now place your meter in series with your circuit. (EX. Remove + supply and connect it to the + meter lead, then take the – lead and complete the circuit.) This will give you amps flowing. Remember amps only flow when the circuit is complete. For high amp situations that a meter can’t handle buy an amp clamp. This device clamps around a wire and measure the amps through magnetic induction. This is to be used in circuits with more than 20amps usually.



That’s all for this installment of Bingo’s Weekly Lessons. I’m extremely sorry for the time it took me to write. I will be on time next time. Again pleas ask questions so I know what you guys rely would like to know. Next time I will be moving on to starting and charging.

Author:  Flying Eagle [ Tue Dec 07, 2004 7:52 pm ]
Post subject: 

Keep up the good work, I like what you are doing here ... glad to have a handy refresher at my fingertips, as I'm sure many others are too.
Tim

Author:  BitAddict [ Fri Dec 10, 2004 10:02 pm ]
Post subject: 

I have a question(not sure if it should be addressed in the thread or directly to the poster)
When you make this statement:
"What you would do is pace the + lead in the circuit and the – to the body or a known good ground."
under "Volt Potential tests"
Would it be essential to perform this test on the circuit before any "consumers" are introduced? If yes, is this for just DC circuits? If no will this method work for both AC and DC?

These maybe silly questions, but hey its in newbie tech! :D

Author:  Bingo [ Sat Mar 19, 2005 1:05 pm ]
Post subject: 

Quote:
I have a question(not sure if it should be addressed in the thread or directly to the poster)
When you make this statement:
"What you would do is pace the + lead in the circuit and the – to the body or a known good ground."
under "Volt Potential tests"
Would it be essential to perform this test on the circuit before any "consumers" are introduced? If yes, is this for just DC circuits? If no will this method work for both AC and DC?

These maybe silly questions, but hey its in newbie tech! :D
You may place the lead befor or after a consumer to help find a bad consumer. If you have a meter that will chance between AC and DC this should work for both.

Bingo-----

Author:  CaptHowdy [ Mon Apr 25, 2005 9:05 am ]
Post subject: 

Quote:
I have a question(not sure if it should be addressed in the thread or directly to the poster)
When you make this statement:
"What you would do is pace the + lead in the circuit and the – to the body or a known good ground."
under "Volt Potential tests"
Would it be essential to perform this test on the circuit before any "consumers" are introduced? If yes, is this for just DC circuits? If no will this method work for both AC and DC?

These maybe silly questions, but hey its in newbie tech! :D
you don't need any consumers.. for example if you place a volt meter across a battery it doesn't blow up, that's because a volt meter has an incredibly high impedence (resistance) so that A. it doesn't blow up and B. doesn't noticably affect your circuit (ie be a consumer itself).

if you're trying to get the voltage drop of a particular component then you place your +/- leads on either side of the component. which order the +/- is in doesn't really matter, if you have them backwards you'll just get a negative reading but you're not interested in the sign here, you're interested in the magnitude.

and as for AC circuits.. you really need an oscilloscope to see what's going on. with an AC voltmeter you just konw there is voltage but you can't really tell how much / when. for example AC current in your house is at 60Hz going from 120V to -120V.. now try and watch a voltmeter read 60 different readings a second.. even if it could the numbers would change so fast you'd never be able to read them..

actually... now that I think about it.. the LCD can't refresh that fast. haha. so in fact, it *can't* read 60 readings per second :)

Author:  Aaron_37 [ Thu Jun 30, 2005 4:42 pm ]
Post subject: 

Ah, reminds me of physics class.

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