Hello everyone,

I'm making a solar simulator with 13 white LEDs in series, they operate in 20V/450mA in full brightness (YUJI VTC Series LEDs 135L).

As a power supply I'm connecting 220V mains to a Variac, then to a full bridge rectifier and to 2x 400V/680uF capacitors in parallel.
Even with so much capacitance, when I increase the voltage on the variac, the LEDs start to shine around 210V, but when I reach 238V, about 70mA, the LEDs start to flicker and I can't reach maximum brightness.

I saw the ripple on the scope and is about 600mV peak-peak.

What am I doing wrong?

Thanks for any help.

Best,

Marcelo.

 

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1. Restricted topics. The following topics are regularly raised however are considered "off-topic" at all times and will result in Your thread being closed without question:
   • Any kind of over-unity devices and systems
   • Devices designed to electrocute or shock another person
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In other words, we are not permitted to discuss this kind of circuit, though you should be able to find other forums that allow discussion of this king of circuit.