Quinetic receiver

[JohnW2]

Blimey. So no current limiting or over-current sensing or PFC etc.? Ah well, everyone wants the cheapest I guess.

Well, the series capacitor is, of course, what does the 'current limiting' but, other than that, you're right (for the cheapos)!

I noticed a relay tick inside. In some ways I prefer this.

I'm sufficiently old and 'suspicious' that I, too, am reassured by the click of a relay!

Kind Regards, John

 

[JohnW2]

Following some un-expected blowing of fuses on the village Christmas lights I did some investigation. The lamps have a series capacitor, 0.47uF bridge rectifier and a smoothing capacitor 10uF.

Similar to my experiences but, as I said, the very cheapest don't seem to even have the smoothing capacity (i.e. rely primarily on the 'smoothing' done by huiman eyes!).

The lamps are nominal 1 Watt and the 200 lamp festoons were, as expected, each pulling about 1 Amp once lit. The manufacturer's response was .... lamps have a 33mA of inrush current.

That seems right. The limitation of the inrush current would be almost totally down to the 0.47F series capacitor, about 6.77k at 50Hz, which I make around 33.9mA at 230V.
For a 200 lamps festoon, you will need a minimum of 7 Amp fuse.

... Please note that the inrush current in the LED lamps can go up to 10 times of the standard current value.

Again, true, but you are talking about a very exceptional situation (200 lamps). In the 'usual' situation, in which there would usually be, at most, a dozen or so lamps (and quite often only 'one or three'), the total 'inrush' current would be pretty trivial.

Kind Regards, John

 

[FranG]

Please note that the inrush current in the LED lamps can go up to 10 times of the standard current value.

Is that "10 times" inrush you refer to for the lamps you use?
The 35mA certainly ties up with a u47 cap on the mains.
Proper LED driver chips/circuits can limit the inrush so it'll be device dependent.
Look at data Sheets for Infineon, Power Integration etc.