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broadgage · 18th Jan 2019, 12:33 am

More modern LED lamps generally contain more sophisticated circuitry than that.
They often contain a switched mode power supply with a constant current output, this runs the LEDs optimally despite variations in line voltage, line frequency, and LED voltage which is temperature dependant.

The difference between the switched mode type and the capacitive dropper is easily determined be a simple test if you have a variac.
Reduce the voltage by say 15%. The switched mode LED will maintain constant light output, and draw more current at the reduced input voltage.
The capacitive dropper type of LED lamp will become dimmer at the reduced voltage and will draw less current.

The switched mode lamps are usually rated for actual supply voltages from about 264 volts down to 200 volts, some types down to 90 volts.

18th Jan 2019, 12:33 am	#93
broadgage Nonode Join Date: Jan 2010 Location: North Somerset, UK. Posts: 2,130	Re: The demise of the fluorescent tube More modern LED lamps generally contain more sophisticated circuitry than that. They often contain a switched mode power supply with a constant current output, this runs the LEDs optimally despite variations in line voltage, line frequency, and LED voltage which is temperature dependant. The difference between the switched mode type and the capacitive dropper is easily determined be a simple test if you have a variac. Reduce the voltage by say 15%. The switched mode LED will maintain constant light output, and draw more current at the reduced input voltage. The capacitive dropper type of LED lamp will become dimmer at the reduced voltage and will draw less current. The switched mode lamps are usually rated for actual supply voltages from about 264 volts down to 200 volts, some types down to 90 volts.