How many LEDs do you have to put in series so that they don’t burn out when you connect them to a 220-230V power source (wall socket)?

Answer

Best,

It is not recommended to connect a number of LEDs in series and plug them into the socket. This is an unsafe situation, because you can feel 220V on every LED and you don’t expect something like that. If you were to use this to decorate a Christmas tree, I would definitely advise against using this method.

But here’s a solution:
– In principle, you can only supply an LED from a DC voltage source.
– if you rectify 220V with a diode or diode bridge, you get 220V x 1.41 = 310V
– a diode is not enough, you also need a capacitor to flatten the voltage (DC voltage) (connect the capacitor between the cathode of the diode and the other pole of the 220V). However, a capacitor that can tolerate a working voltage of 310V DC is hard to find…
– an LED has an average of 1.6V. This of course depends on the characteristic of the LED used. This means you need 310 / 1.6 = 194 LEDs to put in series. The condition is, however, that these 194 LEDs have a similar characteristic, otherwise you will get an imbalance and the LEDs could quickly die.
– an LED is actually current controlled. This means that you basically need to put a resistor in series. It can also work without a resistor, but then you might want to place a coil in series with the LEDs. A coil has the property of making the current more stable. Oh yes, the current at an LED is between 10 to 20 mA for proper operation.

It remains an unstable and dangerous solution. I would recommend that you create a usable DC voltage from the 220V (eg a 24V laptop adapter) and then use small series circuits with LEDs. (eg 15 LEDs connected in series with that 24V).

Good luck with your LED circuit and beware of the dangerous 220V!