➢Step descriptions:

✦Step 1:-Bend the pin C of BD139 to the back, pin B was soldered to the 22K resistor together.

✦Step 2:-Solder the pin of BD139 to the negative pole of the variable resistor. The B-pin and 22K resistors are soldered to the variable pole of the variable resistor.

✦Step 3:-Follow the steps above to make three variable electronic devices.

✦Step 4:-Put three electronic devices in parallel with wires.

✦Step 5:-Connect the four wires on the RGB light strip to the top of the C pin of the three BD139, and connect the positive pole to the positive position of the variable resistor of the first BD139 device.

✦Step 6:-Connect the 12V power supply to the positive and negative poles of the variable resistor of the first DB139 device.

Product list:

『BD139 transistor 』  view more ⇒https://www.utsource.net/itm/p/836289.html

『22k resistor』  view more ⇒https://www.utsource.net/sch/22k%20resistor

『RGB strip LED  』

『50k preset』  

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