Led Driver Circuit Using Transistor

Even fewer parts.

Led driver circuit using transistor. Therefore the transistor cannot turn on. When the switch of the circuit is open no current flows to the base of the transistor. High power led driver circuits. The t2 transistor can be bc547 if you use only usual leds the 20ma versions but it is recommended to use bd135 bd137 or bd139 because they have a higher power dissipation.

Bipolar junction transistors need base current and sufficient positive voltage to the collector in order to provide amplification. An led driver is an electronic circuit that utilises a transistor to switch power to an led. You then have the choice of implementing your driver circuits using discrete transistors or transistors integrated in a semiconductor integrated circuit ic with other led related functionality. Compared to the previous simple current source using two transistors this circuit has.

Much higher dropout of 2 4v which will significantly reduce efficiency when powering only 1 led. If the led has a higher power requirement then it is best to use an npn transistor as a driver. One typical circuit topology used to drive leds is the linear topology in which the transistor operates in the linear region. The schematic of the led driver circuit we will build is shown below.