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ILER-DDS V2.1 VFO/DDS.
Page 7
Note 1. R4
R4 is adjusted to obtain the best contrast of the LCD.
Note 2. R5 values
Your kit may have three types of similar LCD.
R5 is different depending on the type of LCD. All resistors are included in the kit, but only need to be used
according to the following table:
LCD Type
R5 (Backlight)
GREEN 0802A (Ver1.0)
10 Ω brown-black-black
BLUE RT0802A
47 Ω yellow-violet-black
BLUE LCM0802C (V1.0)
47 Ω yellow-violet-black
You can vary slightly the R5 value.
< R5 (less): increases backlight (R5 can never be 0 Ω).
If you want the maximum level of backlight you can connect the pin 15 of the LCD directly to 5V, but note that you
can increase the total consumption by about 20mA.