Dear All
I need to make an LED Tube light in five feet long,
I bought 60 nos 5050 SMD LED.so which is the sutable
connection is parellel or series ?How many LED can connect
in a parellel circuit 12 v dc and which resistor should use their?
I think to connect 60 nos LED in one row.
LED details;
smd led 5050
for.volt=3.6
for current=300ma
input v=12 or ?
if you use 3 LEDs in series, volt drop = 3 X 3.6 = 10.8 V, Vsupply = 12, Volts to loose = 12 - 10.8 = 1.2V, therefore series resistor = 1.2/.3 = 4.0 ohms, so 20 chains @ .3A each, is a 20 X .3 = 12V, 6 A PSU. For 24V PSU, 6 LEDs in each chain, so 2.4 V to loose at .3 A = 8 ohms, so PSU for 10 chains = 24 V @ 3A.
Frank
If you connect all 60 in series these will take 60 X 3.6 = 216 Volts at .3 A. But you have AC, so you need a bridge rectifier, to turn the AC into DC. and you need a 230-216 = 14Volts to loose at a current of .3A = 14/.3 = 47 ohm resistor which will dissipate .3 X14 ~ 5W.
BEWARE THIS STUFF IS DANGEROUS!!!!
Frank