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Section 2, switch testing

  • Willluvstafish
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04 Feb 2019 18:26 #26788 by Willluvstafish
Section 2, switch testing was created by Willluvstafish
New to the page, already learned a lot. But I'm having a little trouble completely understanding the switch testing as I was not traditionally trained in electrical theory. So let me ask, if you have a good working circuit and voltage is successfully going through it's load (motor etc) and completing it's path to ground, if you put your voltmeter ground on ground and and meter positive on the volt suppy wire, it should read 0 volts while current is flowing because available voltage is being used. Am I correct? Because in pull down switch design if switch is working it says you should show 0 volts while switch is connecting the circuit. But I noticed in pull up testing if the switch is connecting the circuit and current is being pulled up to the computer he says it should read 12 volts (,if it's a 12 volts system). Is this because the large resistor in the computer is so strong that the voltage does not have a successful path to ground therefore 12 volts is available even with the path connected? I hope I asked this good enough lol. Thanks

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  • pole71
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04 Feb 2019 21:21 - 04 Feb 2019 21:22 #26795 by pole71
Replied by pole71 on topic Section 2, switch testing

Willluvstafish wrote: if you have a good working circuit and voltage is successfully going through it's load (motor etc) and completing it's path to ground, if you put your voltmeter ground on ground and and meter positive on the volt suppy wire, it should read 0 volts while current is flowing because available voltage is being used. Am I correct?


No. Voltage supply should remain. Voltage will drop across resistors (load).

Kirchhoff's Voltage Law says that the sum of all voltage drops in a circuit is equal to the source voltage.

www.electronics-tutorials.ws/dccircuits/...ffs-voltage-law.html






"Knowledge is a weapon. Arm yourself, well, before going to do battle."
"Understanding a question is half an answer."
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Last edit: 04 Feb 2019 21:22 by pole71.
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06 Feb 2019 05:51 - 06 Feb 2019 05:53 #26820 by Andy.MacFadyen
Replied by Andy.MacFadyen on topic Section 2, switch testing
Not much any of us can add to pole71's great explanation , the fall back way of thinking of electrical current and voltage is to think of it as water or air flowing through a pipe. A switch is like water tap when it is off pressure (voltage) builds up behind it.

"It is the nature of every person to error, but only the fool perseveres in error." Marcus Tullius Cicero
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06 Feb 2019 06:59 #26824 by Willluvstafish
Replied by Willluvstafish on topic Section 2, switch testing
Thank you very much for the responses. I definitely understand it correctly now
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