Tuesday, September 21, 2021

LED Bars

Two LED bar graphs. You would think they would be much alike, but no.

On the left: LTA-1000Y (2017 Thailand.) On the right: FJB10Y.

The polarity is reversed. The LTA has anode on the side of the first pin. The FBJ has the cathode on the side of the first pin.

The obvious difference: face colour grey vs face colour black.

Light colour is similar, but brightness is much different. I need to use 470 ohm resistor with the LTA, and a 2K ohm resister with the FJB.

I did some extra research on another convention, for multi-coloured bars. Is 'red' on top or on the bottom of the bar?:

  • AVAGO HDSP-4832 has R/R/R/Y/Y/Y/Y/G/G/G with pin 1 as RED anode.
  • KingBright DC7G3HWA has G/G/G/G/G/G/G/R/R/R with pin 1 as GRN anode.
  • Fairchild MV5A164 (obsolete) has R/R/R/Y/Y/Y/Y/G/G/G with pin 1 as RED anode.
  • Fairchild MV5C164 (obsolete) has G/G/G/G/G/G/Y/Y/Y/R with pin 1 as GRN anode.
  • KYX B10BBGYR has B/G/G/G/G/Y/Y/Y/R/R with pin 1 as BLU anode.
  • MT1025CTF has G/G/G/G/G/Y/Y/Y/R/R with pin 1 as GRN anode. Pin 1 (unmarked) at side that has print.
  • SunLED XGMDKVGX10D has 10+10 bi-colour LEDs to interpolate between GRN to YLW to RED. To use them, 2k Ohm on R and 470 Ohm on G works well. Unfortunately, it is a common-cathode setup, which makes it useless for standard LED drivers.

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