LED control_2

Light only works between 2 - 6.21 volts. Is that just like a normal led?

In EC we tend to aim for a LED current of 20mA (0.02A). LED’s these days can be so bright that less current can be used in real life circuits. When the transistor is fully on there is little volt drop across it which can be ignored in this circuit. The volt drop across the LED we want to set as 2V which means we need to drop 3V across the collector resistor. For 3V and a current of 20mA the resistor should be R=3/0.02, which is 150 Ohm. Your base resistor is far too low and wastes current and drives the transistor too hard. The transistor gain (beta) defaults to 100. This means base current has to be 1/100 of the collector current, which is 0.02/100, which is 0.0002A or 200uA. Since, with the transistor turned on, the base voltage will be 0.7V we need to drop 5-0.7=4.3V across resistor, so R=4.3/0.0002 which is 21.5k, round up to 22k. Finally, I would add a relatively high value resistor between base and ground, say 100k, so that the transistor base is held to 0V when switch is open. Hope this helps.