Hi all, this is my first thread here being new forum member and I'll try to be as accurate and explaining as possible.
Please do not hesitate to correct me on any shortcomings from my side in this thread. I am an absolute beginner when it comes to electronics.
The idea is to eventually power this circuit with 12V DC and attach 2-3 1W 350mA LED in series with an LM317T as a constant current source.
So, I set up the following test circuit and connected P1 to a 7V/2A rated DC power supply. P2 has a 1W 350mA LED attached in series with a 1 Ohm 1/4W resistor.
The datasheet for the used IRL540N can be found here: https://cdn-reichelt.de/documents/datenblatt/A100/IRL540N_IR.pdf
When powered on the LED is barely lit and turning VR1 does dim the LED. However it is fairly obvious I am unable to light LED to it's full brightness, by far.
The voltage across the LED is 3.1V, but when attaching the multimeter in series I get 0.012mA current flowing through the resistor and LED (Yes, that's 0.012 milliAmps).
As a test I connected the LED and 1 ohm resistor directly to P1+ and Pin3 of the NE555P and disconnected R3 and Q1 from the circuit. This way I am able to fully light the LED and dim it almost completely. Current is about 270mA.
The question is, why is there no current flowing when the IRL540N is connected?
Please do not hesitate to correct me on any shortcomings from my side in this thread. I am an absolute beginner when it comes to electronics.
The idea is to eventually power this circuit with 12V DC and attach 2-3 1W 350mA LED in series with an LM317T as a constant current source.
So, I set up the following test circuit and connected P1 to a 7V/2A rated DC power supply. P2 has a 1W 350mA LED attached in series with a 1 Ohm 1/4W resistor.
The datasheet for the used IRL540N can be found here: https://cdn-reichelt.de/documents/datenblatt/A100/IRL540N_IR.pdf
When powered on the LED is barely lit and turning VR1 does dim the LED. However it is fairly obvious I am unable to light LED to it's full brightness, by far.
The voltage across the LED is 3.1V, but when attaching the multimeter in series I get 0.012mA current flowing through the resistor and LED (Yes, that's 0.012 milliAmps).
As a test I connected the LED and 1 ohm resistor directly to P1+ and Pin3 of the NE555P and disconnected R3 and Q1 from the circuit. This way I am able to fully light the LED and dim it almost completely. Current is about 270mA.
The question is, why is there no current flowing when the IRL540N is connected?