Three primary color display circuit

The three-primary color principle is the basis for forming color image information, as shown in the three-primary color circuit in the figure. Arrange 6 three-color light-emitting diodes
in a row and connect PN junctions of the same color in series to form a color-changing light-emitting unit. For the convenience of production, the power supply uses a 17V switching
regulated power supply. Since the proportions of the three colors of red, green, and blue that make up white light
are different, the currents passing through the blue color PN junction are also different. For
this purpose, the current-limiting resistance of each light-emitting unit can be adjusted to
control the current through the red and green PN junctions at 9-12mA, and
the current through the blue PN junction at around 4-5mA.
    In this circuit,
the current limiting resistors RR, Rr;, and RH corresponding to the red, green, and blue PN junctions are 8200, 82fl, and 300fl respectively.
For different types of light-emitting tubes, the above resistance values ​​may be different. .
In order to meet the needs, 10 such color-changing light-emitting units are connected in parallel to form a light-emitting surface, and three switches are used to control the three-color
light-emitting surfaces respectively. Structurally, 60 three-color light-emitting diodes can be installed on a universal experimental circuit board in a 6×lo array. The distance between the holes on the circuit board
and the pins is just right, eliminating the trouble of drilling holes and making printed circuits.