Author Topic: expected voltage readings  (Read 1803 times)

Offline fisherman

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expected voltage readings
« on: March 13, 2015, 09:43:45 PM »
hello everybody

im writing my G3 this week and want to be confident if i get asked this, 

before hand i want to ask these couple of questions and i will provide my answers also, i want anyone to correct me if im wrong please

the correct readings a meter would read if, the following was measured

resistance across an OPEN switch would read O.L on a digital and infinity (side ways 8 ) on an analogue
resistance across a CLOSED switch would read about 0 ohms,
resistance across a load equals mesaurable resistance
voltage across an OPEN switch is applied voltage.
voltage across a closed switch is 0V
now this is were i get confused

voltage across an energized load equals zero
voltage across a de-energized load, would it be 120 V???

correct my mistakes please

i have uploaded a picture, that i drew fast using paint of a ladder diagram.

please make references


Offline Porcupinepuffer

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Re: expected voltage readings
« Reply #1 on: March 14, 2015, 01:38:18 PM »
Where did you get the info for the two questions where you get confused?

Voltage across an energized load would be present, (SW2 in your diagram) or the load wouldn't work.

Voltage across a de-energized load would be zero. (SW1 in your diagram) With no difference in electrical pressure or potential (voltage), the load would be de-energized.