If the switch is closed (connected) the voltage across it will read 0V. If the switch is open (disconnected) the voltage across it could be anything, it just depends on what the voltage between the wires going into the switch is.
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.
function of capacitive voltage transformer is measure high transmission voltage with low range voltmeter and oprate the relay circuit to oprate CBs.
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!
For an ideal switch, there will be no voltage drop across it. In reality, there will be a very small voltage drop, and this will be dependent on how well made the switch is, and what it is made out of.
The voltage measured across an open in a series circuit is the equivalent of the sourse voltage.
Voltage
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.
function of capacitive voltage transformer is measure high transmission voltage with low range voltmeter and oprate the relay circuit to oprate CBs.
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!
Anything that a voltmeter is measuring has some internal output impedance. If the voltmeter had a low input impedance, these two impedances would form a voltage divider and reduce the voltage measured. The voltmeter has a high input impedance so that it does not affect ("load down") the thing it is measuring.
"Voltage" is the difference in electrical potential between two points in a circuit.If the voltage across the light bulb is what you want, then first make sure thatthe meter in your hand is a voltmeter, and then touch each probe of the voltmeterto one of the connections on each side of the light bulb.If you want to determine whether power is getting to the light bulb, you stillhave to do it by measuring the difference in voltage between two points. Youcould use your voltmeter to measure the voltage between one connection atthe bulb and one connection at the switch. If the power is getting from theswitch to the bulb, then the voltage between the switch and the bulb shouldbe zero (or very small).The voltage between the two connections to the switch should be zero whenthe switch is ON, and mains voltage (115 or 220) when the switch is OFF, etc.I have worked alongside individuals in the past who claimed that they coulddiscern the presence of voltage, and even measure it, by licking their fingerand touching it firmly to the circuit point in question. I don't know how manyof them are still alive, and I strongly recommend AGAINST that technique.
For an ideal switch, there will be no voltage drop across it. In reality, there will be a very small voltage drop, and this will be dependent on how well made the switch is, and what it is made out of.
The full circuit voltage
The voltage measured across an open in a series circuit is the equivalent of the sourse voltage.
A voltmeter needs to be connected in parallel with the part of the circuit you are checking. It records a change in voltage, and has a high internal resistance, so it cannot be connected in series unless you want to screw up the circuit. Set the meter to AC or DC volts and place the wires of the terminal across the resistor, switch, or any other potentially resistive part of the circuit.
You either have a bad switch or you need to check your fuse or relay for your a/c. To check your switch: you need a multimeter or voltmeter. You'll need to get to the back of your switch, keep it plugged in and find your power wire to the switch. Then put the positive end of the voltmeter in the back of the connector into the power(don't push to hard or you'll damage the connector). Then put the negative end of the voltmeter on a good ground on your frame or something that touches your frame. You should get a voltage reading of 12 volts. If there's no voltage than somethings wrong with the wiring up to your switch. If there is voltage, than you need a new switch.
It is the maximum voltage to which it has been calibrated, but this may be set out in separate ranges selected by a switch on the front panel.