To test for resistance in a circuit, the circuit should be de-energized.
Isolating energized components can be accomplished by placing the energized parts at least _____ feet high and out of reach, or by guarding.
If the test shows that there is a continuity between the phase leg and the neutral with no load connected, then that circuit should not be energized. If the circuit was energized then the fuse or breaker protecting that leg will trip the circuit open.
Because an ohmmeter works by putting a potential difference (voltage) across a load and measuring the resulting current (the current will be inversely proportionate to the resistance). In a live circuit there is already current flowing through the load so (at best) the reading will be inaccurate, at worst the meter will be damaged.
Open
Firstly turn of the power before this test...Using a resistance or continuity tester you should get the following results:Short circuit: Very low resistance (nearly 0 ohms) or the bell will ring.Open circuit: Very high resistance (Somewhere in the range of Mega ohms) or the bell will not ring.The reason for this is because and open circuit has a gap in it (which has high resistance).The short circuit has wires that are crossed and so has a really low resistance.
An open circuit essentially has an infinite resistance. It is shown on digital multimeter as OL. (Open Line) A short circuit should read zero, or nearly zero, depending on the accuracy of the meter.
No, the circuit should not be energized when checking the resistance of a circuit.
If the test shows that there is a continuity between the phase leg and the neutral with no load connected, then that circuit should not be energized. If the circuit was energized then the fuse or breaker protecting that leg will trip the circuit open.
Because it is your life you should always think that what ever you are going to work on is hot or energized. That is what they make meters for to tell you if the circuit is dead or energized what do you do if the neutral is broke or open.
No. There should be substantial resistance only where the circuit design needs it and wants it, and as little as possible everywhere else in the circuit.
The most important piece of electrical safety equipment that is used in the electrical trade is a voltage detector. You never start or do anything to a circuit until the circuit is tested and confirmed de energized. Once the circuit is confirmed de energized pad lock it in the off position and keep the key on your person. Never ever take any ones word for it that the circuit is turned off. Get the meter out and confirm that the circuit is de energized for yourself.
0 ohms
To increase (current) flow in a circuit you increase voltage (or decrease resistance). Ohm's Law: Current = Voltage divided by resistance
The voltmeter has an internal resistance, which should be as high as possible. As this resistance draws current from the circuit under test, it will affect circuit operation. This is more pronounced in a high impedance circuit because the current drawn flows through higher resistances.
Because an ohmmeter works by putting a potential difference (voltage) across a load and measuring the resulting current (the current will be inversely proportionate to the resistance). In a live circuit there is already current flowing through the load so (at best) the reading will be inaccurate, at worst the meter will be damaged.
Open
if not disconnected you will measure the resistance of the circuit in parallel with the resistor.
Firstly turn of the power before this test...Using a resistance or continuity tester you should get the following results:Short circuit: Very low resistance (nearly 0 ohms) or the bell will ring.Open circuit: Very high resistance (Somewhere in the range of Mega ohms) or the bell will not ring.The reason for this is because and open circuit has a gap in it (which has high resistance).The short circuit has wires that are crossed and so has a really low resistance.