I recently purchased 2 little voltmeters they look like the sort that would go in a control or instrument panel they are connected with just 2 wires which provide the operating supply ( they light up green and red) however the green one states it will work between 20and 500 volts and the red one between 60 and 480 volts. When they are both on the green one indicates normally around 241 volts the red one shows 235 volts why the discrepancy I know it's not much but makes you wonder if one of them is lying. Secondly I've noticed that the green one tracks voltage changes faster than the red one and that a few times the green one jumps down to 238 then up to 241 multiple times while the red one stays the same and I think can see a slight flicker in my filament lamps when this is happening incidentally both meters are connected to the same plug a 2 pin 5 amp one
As you drive you speed up and slow down, there are traffic lights to stop at, slow drivers in front of you and general delays.
There are two types of speed cameras.
The fixed cameras record your peak speed at one specific point on the road, so long as you don’t pass that camera at more than the speed limit you won’t get a ticket in the post. So you can have a higher peak speed in between those cameras as it is is only a snapshot of your speed at a specific point in your journey.
The average speed cameras calculate your speed over a certain distance, again you can pull out and exceed the speed limit to pass a slow vehicle without getting a ticket in the post as your average speed was low because you were behind that slow vehicle.
My new sat nav calculates the average speed I am doing between the cameras, which allows judgement calls on the likelihood of getting one of those tickets in the post. However the authorities are aware of this and locally on the A449 above the Claines roundabout there is often a mobile traffic camera van parked in front of the fixed speed camera to catch those who are speeding then slow down to pass the camera.
Now apply the same principles to volt meters. The voltage is rising and falling at 50 hertz, fifty times a second it rises and falls, in fact it passes through zero a hundred times a second, also the load changes increasing and decreasing the peak voltages, Just like a driver driving through Nottingham constantly adjusting the speed of the vehicle, voltage rises and falls.
A volt meter can be measuring the peaks or it can be measuring the average and there can be a variation in how often it does it.
Do neither of your meters is showing the peak voltages will be showing the highest voltage present. But I’m not the guy to go into detailed explanations of what volt meters you should choose for what you need to determine.
I just work on the basis that the AC volt meters I use give an indicative value allowing me to have some sort of idea of what is going on, not an absolutely precise measurement.
As you drive you speed up and slow down, there are traffic lights to stop at, slow drivers in front of you and general delays.
There are two types of speed cameras.
The fixed cameras record your peak speed at one specific point on the road, so long as you don’t pass that camera at more than the speed limit you won’t get a ticket in the post. So you can have a higher peak speed in between those cameras as it is is only a snapshot of your speed at a specific point in your journey.
The average speed cameras calculate your speed over a certain distance, again you can pull out and exceed the speed limit to pass a slow vehicle without getting a ticket in the post as your average speed was low because you were behind that slow vehicle.
My new sat nav calculates the average speed I am doing between the cameras, which allows judgement calls on the likelihood of getting one of those tickets in the post. However the authorities are aware of this and locally on the A449 above the Claines roundabout there is often a mobile traffic camera van parked in front of the fixed speed camera to catch those who are speeding then slow down to pass the camera.
Now apply the same principles to volt meters. The voltage is rising and falling at 50 hertz, fifty times a second it rises and falls, in fact it passes through zero a hundred times a second, also the load changes increasing and decreasing the peak voltages, Just like a driver driving through Nottingham constantly adjusting the speed of the vehicle, voltage rises and falls.
A volt meter can be measuring the peaks or it can be measuring the average and there can be a variation in how often it does it.
Do neither of your meters is showing the peak voltages will be showing the highest voltage present. But I’m not the guy to go into detailed explanations of what volt meters you should choose for what you need to determine.
I just work on the basis that the AC volt meters I use give an indicative value allowing me to have some sort of idea of what is going on, not an absolutely precise measurement.
