Thanks! Appreciate your time and excuse my ignorance on the subject.

10k resistor is on the way... In the meantime I think I got it to work, but I want to check it against your expertise.

the laser module I am using

circuit

I am using a sliding pot to control the PWM output (0~5V). The laser is off when the pot is all the way to the left and seems to be at full power when the pot is all the way to the right.

I should still add a 10K resistor between the Arduino PWM pin and laser right?

Is there any other problem with the circuit?

Thanks.