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I'd say it wouldn't be -40 volt, but in fact 40 volt. I'm guessing you measured it with a multimeter and had your polarity (positive/negative) mixed up when you placed the leads on the telephone line.

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The nominal voltage between tip and ring on the telephone line is 48 VDC (it is provided by a 24 cell lead acid battery in the central office) but this can be reduced by line drop by as much as 9 VDC depending on how far you are from the central office. Tip is connected to the positive side of the battery and ring is connected to the negative side of the battery. The tip and ring twisted pair is isolated from ground, so either can be used as your multimeter reference as long as you are aware of polarity so the reading of the multimeter will make sense.

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Why a lamp cannot run with the telephone line voltage?

A lamp can be run by power from a telephone line.


What is the voltage of a telephone socket?

The voltage of a standard telephone socket typically carries around 48 volts DC when the line is idle. During a phone call, this voltage can drop to about 6-12 volts AC due to the conversation's signal. The system is designed for low voltage to ensure safety and compatibility with telephone devices.


How you calculate the line -line voltage?

Line-to-line voltage in a three-phase system is calculated using the formula ( V_{LL} = \sqrt{3} \times V_{LN} ), where ( V_{LN} ) is the line-to-neutral voltage. This relationship arises because the line-to-line voltage represents the voltage difference between two phases, while the line-to-neutral voltage is the voltage from a phase to the neutral point. If you have the line-to-line voltages directly measured, you can also use the voltage differences between any two phases to determine the line-to-line voltage.


How do you convert 3 phase RMS line-line voltage to RMS line-neutral voltage on an unbalance system Basically how do you calculate using trig for all 3 phase?

The term, 'unbalanced system' refers to an unbalanced load. Under normal circumstances, an unbalanced load leads to unbalanced line currents. The line voltages are determined by the supply and remain symmetrical, even when the load is unbalanced. As your question refers to a 'line to neutral' voltage (i.e. a phase voltage), you must be referring to a star (wye) connected load, in which case the phase voltage (line to neutral voltage) is 0.577 (the reciprocal of the square-root of 3) times the line voltage (line to line voltage).


What is a line to line voltage?

In a 3 phase system, the voltage measured between any two phase is called line to line voltage.And the voltage measured between line to neutral is called phase to neutral (line to neutral) voltage.AnswerThere is no such thing as a 'phase-to-phase' or a 'phase-to-neutral' voltage. The correct terms are 'line-to-line' and 'line-to-neutral'.The voltage between any two line conductors is called a line voltage.In a three-phase, three-wire, system, the line voltage is numerically equal to the phase voltage.In a three-phase, four-wire, system, the voltage between any line conductor and the neutral conductor is called a phase voltage. The line voltage is 1.732 times larger than the phase voltage.

Related Questions

Why a lamp cannot run with the telephone line voltage?

A lamp can be run by power from a telephone line.


What is the voltage of a telephone line?

48 VOLTS


Why telephone line has negative voltage?

A negative live voltage is used to prevent electroytic corrosion on the copper wires.


What is the voltage of telephone line in Pakistan ptcl?

it has 52volt dc off hook


How do you measure for voltage on a home telephone line?

To measure voltage on a home telephone line, you'll need a multimeter set to the DC voltage range. Connect the multimeter probes to the two wires of the telephone line, typically the tip (positive) and ring (negative) wires. A properly functioning phone line should show a voltage between 40 to 60 volts when the phone is on-hook (not in use). Always ensure safety by avoiding contact with the wires and using insulated tools.


What is the voltage of a telephone socket?

The voltage of a standard telephone socket typically carries around 48 volts DC when the line is idle. During a phone call, this voltage can drop to about 6-12 volts AC due to the conversation's signal. The system is designed for low voltage to ensure safety and compatibility with telephone devices.


A telephone-repair technician uses a meter to measure voltage on a phone line. This meter is an example of .?

it is hardware not software


How many volts can a landline telephone handle without blowing?

Since the ringer voltage across the twisted pair is 120 VAC RMS the telephone can definitely handle that. Given the fact that the telephone is also supposed to survive induced surges from nearby lightning strikes to the line the telephone should be able to handle over 1000 V common mode impulses (but I don't know the exact limit). No telephone is expected to survive a direct lightning strike to the line (which could be millions of volts). Note: common mode means the voltage is applied between the twisted pair lines (both at about the same voltage) and ground. If the survivable common mode voltage were to be applied across the twisted pair instead it would severely damage the telephone.


What is a easy way to extend a telephone line?

You can use an in-line coupler to extend a telephone line.


How you calculate the line -line voltage?

Line-to-line voltage in a three-phase system is calculated using the formula ( V_{LL} = \sqrt{3} \times V_{LN} ), where ( V_{LN} ) is the line-to-neutral voltage. This relationship arises because the line-to-line voltage represents the voltage difference between two phases, while the line-to-neutral voltage is the voltage from a phase to the neutral point. If you have the line-to-line voltages directly measured, you can also use the voltage differences between any two phases to determine the line-to-line voltage.


What is the voltage required to activate a telephone answering unit connected to a telephone?

48 volts


What is edge speed in electronics?

A voltage is applied to a signal line. The voltage of the line changes gradually from 0 to +V. The "edge speed" is the rate of change of voltage of the line. A voltage is applied to a signal line. The voltage of the line changes gradually from 0 to +V. The "edge speed" is the rate of change of voltage of the line.