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With switch s1 closed meter m4 reads 4 volts across r3. what voltages would the meter read across r1 and r2?
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When measuring voltage drop across a switch what is the maximum allowable voltage drop?
The voltage drop should be as close to zero as would be readable by a typical volt meter. If it is measurable you likely have a problem with corrosion or oxidation in switch that is increasing resistance. If you can measure a voltage drop across a closed switch contact, replace the switch. Or the switch is open, try flipping the switch!
Why does your digital multimeter read ac and dc on same terminal?
The switching of the circuitry is done internally for the different voltages. This is done when you move the switch on the front of the meter from AC to DC.
How can wire up the voltmeter to measure 3 phase supply without rotary switch?
There are only two ways this can be accomplished. The most economical way to measure three phase voltages is with one meter and a rotary switch, that has an off position, to connect the one meter to each of the three phases one at a time. The other approach is to have three volt meters connected to each phase to measure each phase individually. With the three meter approach you will still need a switch in each meter so that the meter can be taken out of the circuit when no reading is needed.
What happens inside a voltmeter when you switch it from a lower to a higher voltage range?
When you switch a voltmeter from a lower to a higher voltage range, an additional resistor is added in series with the meter, increasing the voltage necessary to create the same voltage drop across or current flow through the actual meter movement.
Assume that the function range switch is on the 20k position and the multimeter displays 1 when the test leads are across an unknown resistor What would most likely cause the meter to display 1?
the function range switch is not set on a high enough scale
When measuring voltage drop across a switch what is the maximum allowable voltage drop?
The voltage drop should be as close to zero as would be readable by a typical volt meter. If it is measurable you likely have a problem with corrosion or oxidation in switch that is increasing resistance. If you can measure a voltage drop across a closed switch contact, replace the switch. Or the switch is open, try flipping the switch!
How do you check hrc fuse?
An ohm meter across the fuse will tell you whether the link is open or closed.
Why does your digital multimeter read ac and dc on same terminal?
The switching of the circuitry is done internally for the different voltages. This is done when you move the switch on the front of the meter from AC to DC.
How can wire up the voltmeter to measure 3 phase supply without rotary switch?
There are only two ways this can be accomplished. The most economical way to measure three phase voltages is with one meter and a rotary switch, that has an off position, to connect the one meter to each of the three phases one at a time. The other approach is to have three volt meters connected to each phase to measure each phase individually. With the three meter approach you will still need a switch in each meter so that the meter can be taken out of the circuit when no reading is needed.
What are the function of different parts of VOM?
The VOM is in the classification of a multimeter. This means that the one meter can do several functions. VOM stands for Volt Ohm meter. In the voltage portion, the meter has the ability to measure a variety of voltages from fractional usually up to 1000 volts. This is both AC and DC voltages. In the ohms portion, the meter has the ability to find the resistance of components. On most good multi meter there is a continuity setting that will have a sound emitted if what you are testing has continuity through it. That setting is very useful in troubleshooting control panels to locate open and closed contacts in energized and de energised relays.
What is the difference between milli volt meter and volt meter?
A milli voltmeter is suitable for measuring voltage/potential difference in milli volts, thus they measure smaller voltages. A regular voltmeter is used to measure comparatively larger voltages.
What happens inside a voltmeter when you switch it from a lower to a higher voltage range?
When you switch a voltmeter from a lower to a higher voltage range, an additional resistor is added in series with the meter, increasing the voltage necessary to create the same voltage drop across or current flow through the actual meter movement.
What are the basic instrument that can be used to directly measure the AC voltages?
Digital Volt Meter (DMM)
What is instrument potential transformer?
it is used to measure very high voltages which can not be measured with volt meter.
How do you check whether supply is coming or not in 3 phase?
Voltage is checked with a volt meter. It doesn't have to be 3 phase. It is used to test any potentials across phase to phase, line to neutral, line to ground or across resistances. Be careful when testing live voltages as a misplace of the meter probes could cause an arc flash that could give you three degree burns to any exposed skin.
What voltage would you expect to measure across closed switch?
Original Correct Answer:The voltage across an open switch should equal the supply voltage.More Detailed Answer:The above answer is basically correct. However, it may not be EXACTLY the supply voltage.This is counter-intuitive at first glance and confuses a lot of people, including electrical engineers. The reason is this. Voltage, Current and Resistance are all interrelated by Ohms Law. Voltage equals Current multiplied by Resistance.It is easy to think that since a switch is open, then you do not have current flow through the circuit. Thus, current times any Resistance is equal to zero volts because the current is equal to zero. Thus, by this logic, you would expect to find zero volts across the switch. In actuality this is true.But, when you insert you meter, you change the conditions of the circuit, and the following is the result.Let's say that you have a circuit with a resistance load like a heater, and a inductive load like a motor. The switch that powers these devices is open, thus their is no current flowing through the resistance or inductive loads.Now you put the meter across the open switch. When you do, you insert a very large resistance in parallel to the open switch. Why? Because to get volts, the meter measures current flow through a known resistance, and then calculates voltage. To keep the resistance from impacting the circuit performance, the resistance is very large. Therefore, when you insert the meter, you will get a flow of current through the meter.Because of this large resistance, the current trough the resistance load, inductive load, and wires is very small. Thus, the voltage drop across the loads and wiring is very small. Therefore, it appears that the entire voltage in the circuit is across the huge resistance in the meter. The result is a voltage reading that is very near the source voltage.Let's do the math. Let's assume you have 120 volts. You also have a resistance of 500 ohms, and a motor winding that has 0 ohms resistance when DC is applied (This is true for motors). The meter has a 10 million ohm resistance.If these loads are in series, the total resistance is 10Million 500 ohms. The 11.9 microamps. By multiplying the current flow to each resistance, you get 6 millivolts across the resistance, no voltage across the motor winding, and 119.994 across the open switch or meter. Since a meter rounds it reading, you would get 120.If the loads are in parellel, you would get the same thing, becuase the switch is in series with both loads. In this example, the motor winding would have all the current flow through it since it is zero ohms, and the parallel resitance load is 500 ohms. Thus, the total resistance is the 10 million of the meter, and this resistance drive the current, and thus the largest voltage drop is at the swtich/meter. You could decide to remove the motor from this parellel circuit. If you did then the then the result is the series circuit above.
What are the basic test instruments in electricity?
A "multimeter" to test resistances, voltages, amperages. An external "clamp" meter to measure high ac currents. A "mega" meter to test insulation.
