Electrical Tips and Tricks
Homemade laser driver
All parts together cost me around 2€. (~2.5$)
The Resistor is to be calculated as follows:
Resistance = 1.25V / max. Current to Diode
The 1.25V is the Reference Voltage of the LM317.
maximum diode current is 250mA:
1.25V/0.25A = 5Ohm
The Variable Resistor can be used to control the current to the diode.
The Current can be calculated with this formula:
I = 1.25V / Resistor + Variable Resistor
Insert the momentary Resistance of the potentiometer here.