The current can be kept constant in the load circuit using the integrated regulator LM350. The presented circuit can be used with currents up to 3 A. The value of the resistor RX is calculated according to the current that is wanted in the load according to the formula next to the diagram. The 1.25 of the formula is the value of the zener diode internal to the LM350. The integrated circuit must be equipped with a heat sink for currents above 100 mA in the load.
