While Bill's circuits with one transistor per 3 LEDs might be a bit much, I don't think anyone is suggesting a single transistor for the whole 5K array.
3 LEDs plus a small ballast resistor = 1 string. 20 strings = 100 mA, or 1.1 W dissipated in the combination of 20 resistors plus 1 transistor. 84 groups = 5K LEDs. If you have known good airflow, you probably can combine more strings per transistor.
ak
3 LEDs plus a small ballast resistor = 1 string. 20 strings = 100 mA, or 1.1 W dissipated in the combination of 20 resistors plus 1 transistor. 84 groups = 5K LEDs. If you have known good airflow, you probably can combine more strings per transistor.
ak