Hi,
I was testing a small circuit I had which I intend to recreate on a larger scale once I had the basics down.
It involves using a micro controller and a P channel MOSFET to switch an LED on. And to later add a ULN2803 to sink the current.
What I found weird is that by adding the ULN2803, the current to the LED drops significantly (20mA to 1mA). I am aware there is a voltage drop across the NPN transistor and that I did not change the value of the resistor value between adding the ULN2803...
ULN2803 Limiting Current Problem
I was testing a small circuit I had which I intend to recreate on a larger scale once I had the basics down.
It involves using a micro controller and a P channel MOSFET to switch an LED on. And to later add a ULN2803 to sink the current.
What I found weird is that by adding the ULN2803, the current to the LED drops significantly (20mA to 1mA). I am aware there is a voltage drop across the NPN transistor and that I did not change the value of the resistor value between adding the ULN2803...
ULN2803 Limiting Current Problem