but the pcb I'm trying to control
any idea what the operating voltage is?
why the transistor
This is an add on to the other post I raised which
Thanks very much Paul! Here's what I can see on the diode... It looks like it says 6b... and a symbol.. Any way I can test it to find out?
Are you sure I need a resistor for each LED? On the other board I tried 5v and nothing happened, tried 12v and the LEDs light up perfectly. There is resistance between the transistor the LED and ground so there must be resistance built in somewhere that I can't see, maybe in the wiring or the LEDs themselves? [EDIT] I just tested and this board seems to have 360 ohms between each LED and ground. The other board which uses 12v LEDs does not have any resistance on the LEDs, but the LEDs are all pairs of two in series. Does this mean that the other board will need resistors on the supply for each pair of LEDs?
I was undecided whether for the fan speed you lit a number of LEDs depending on speed or just one to show current speed but yes then one for the heat setting and one if AC is on (I think that's what the big one is)So does that mean then that the transistor emitter is putting out 5-6 volts and the rest of the board (switches and potentiometers) are running on 12?
If the LEDs are running on 5 volts could I just use the arduino pins to switch to ground? I'm using a teensy 3.2 just for this job so plenty of inputs and outputs available...