Low voltage reading with new LED bulbs

[bernardgreen]

set distance apart so the inductance and capacitance cancel each other out.

Impractical as the "set" distance would be determined by too many variables depending on the method of installation.

I am informed in South Africa they had to convert the power lines to DC

DC is used for long distance transmission as it avoids the need to synchronise phase and frequency at interconnected power stations.

A suppressor has a capacitor in it which cures the problem the resistor is only to discharge the capacitor.

When used as a contact suppressor the resistor limits the current from the capacitor when the contacts close and shorts the capacitor. In the snubber mode ( across an LED lamp ) the resistor has no function other than to act as a fuse should the capacitor fail and put a short across Switched Live and Neutral

 

[ericmark]

When used as a contact suppressor the resistor limits the current from the capacitor when the contacts close and shorts the capacitor. In the snubber mode ( across an LED lamp ) the resistor has no function other than to act as a fuse should the capacitor fail and put a short across Switched Live and Neutral

In other words we use trial and error to work out what value is required to match the transmission line. I will admit when I read the info on transmission lines it seemed an impossible task to match as it is dependent on current drawn.

However set the VSWR on an aerial at 30 watt and it seems still to be valid at 5W just one of those subjects I never quite got my head around. Clearly at 144.500Mhz it's important but at 50Hz not really an issue.

 

[JohnW2]

In other words we use trial and error to work out what value is required to match the transmission line. I will admit when I read the info on transmission lines it seemed an impossible task to match as it is dependent on current drawn.

As has been pointed out to you a number of times, transmission line considerations are totally irrelevant at 50 Hz (at least, unless your circuits are literally thousands of miles long!)

Kind Regards, John

 

[JohnW2]

DC is used for long distance transmission as it avoids the need to synchronise phase and frequency at interconnected power stations.

IIRC, even (at least some of) the cross-channel (France -> England) transmission uses DC, doesn't it?

Kind Regards, John

 

[bernardgreen]

In other words we use trial and error to work out what value is required to match the transmission line.

In pure theory send 50 Hz power along twin and earth can be considered as a complex transmission line. It is complex due to the close proximity of he CPC making it three inter-meshed transmission pairs. Thus any calculation of actual values for matching would be very difficult and likely to produce impractical values for the matching components.

For switch drops it is not a true transmission line as no power travels along the transmission line. ( if it did the switch would get hot ).

For domestic work transmission line effects are ( probably ) a bit of a red herring.