Hi new member here and hoping somone can answer what is probably a simple question to the experienced. I am making a model project and am lightng LEDs using a nano and a ULN2803 transistor array. I am using high brightness LEDs and want to drive them at around 25mA.
At 5v and using a 68ohm resistor i get 26mA running the LED direct. Now when I connect into the circuit with the nano and ULN2803 the LED is only getting 17mA. I assume this is due to the internal resistance of the ULN chip. Will I run into any problems if I just reduce the resistor so I achieve my 25mA.
Many thanks for any advice
Dave
Thanks
I will be running 3 LEDs in parralel with their own resistor from each output pin across all 8 outputs so 600mA total. I have read that a MOSFET would be more efficient in this application, what would be a suitable logic level MOSFET array that would drop right in instead of the 2803?
Sourav Gupta
PermalinkThe Darlington pairs are rated for 500mA 50V output. It wouldn't be a problem but the 2803 will heat up.
- Log in or register to post comments
Joined February 12, 2018 696Monday at 02:11 PM