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My prelit tree has strings of LED lights and each bulb has three wires going to it. Looking on the web there are a number of sites that describe how to repair strings wired in series that have two wires per bulb. However I cannot find any reference to strings with three wires per bulb.
Since you are looking to string the LED's together, you will need to first choose a type of light. We will assume until otherwise that your lighting option is 12volts, since that is fairly common in cars. What you will need to find is the amperage rating of each string of led lights, then you will need to add it together.
I tried to fix same LED Christmas's light. It has resistor and diode inside. One string 50 LEDs divide to two parts. 25 LED bulbs connected in series and one diode and resistor. Measuring current gave half sine wave, amplitude 60 mA. So the average is 20 mA. Smart inventors just replaced incandescent bulb with LED and added diode and resistor.
If you know (or can measure) the LED current for each LED (end therefore for a series) and the voltage drop of each and the applied voltage, you could calculate the resistance and wattage of a resistor to limit the current to a safe value. $$ R = { V_{supply} - n V_{LED} \over I_{LED} } $$ $$ P = {I_{LED}}^2 R $$
I have a LED Christmas lights string, which consists of two circuits of LEDs connected serially. It is working directly on 110V AC. Most LED sockets have 2 wires connected to them, some have three. There is a 110V socket on the other end of the string, so these can be chained together.
Chop the lights off, measure the current/voltage in both directions, and then build something to drive it with a PIC or Arduino to control it. \$\endgroup\$ – Neil_UK Commented Jan 24, 2022 at 18:51
The big problem is the lamps you're using, those 7 watt incandescent bulbs are a thing of the past. You need to go get some LED type christmas lights, these draw less than 1/2 watt each. A typical string of 100 lights is ~ 40 watts, so I'm guessing you could string up to 5-6 of these together, but definitely follow the recommendation on the ...
LED drivers for household lights are often constant current switching power supplies. For a typical simple ...
Almost every LED light I've tested (hold an AM or shortwave radio antenna nearby) emits RFI or EMI across a vast frequency range. The EM noise comes either from the base of the bulb, or from some box or wall-wart supplying a DC voltage to the LED fixture. Is there any common solution to fixing or reducing this EMI?
I then used 'water clear' blue led, which lights up very brightly based on some DC component of the rectified signal and some residual carrier wave as well. The load is capacitive, seeing that crystal earphones are essentially a pietzo element (2 plates separated by an insulator - the pietzo crystal material.