# How is powering an LED with a 9 volt battery possible without burning the LED?

I used a 220 ohm resistor with a 9V battery and the LED works fine. However, most sources say the forward voltage in a red LED is typically only ~2 volts. Going by this logic, the LED should have burned out, as resistors only limit current not voltage. If this is a stupid question, I’m sorry. I’m relatively new at electronics.

• do more research before posting your question ... for instance, measure the voltage across the resistor Sep 29 '19 at 22:16
• The resistor drops the voltage, so the LED only "sees" ~2 volts, as you say. Read about voltage dividers, voltage drop, and Kirchhoff's voltage law. Sep 29 '19 at 22:17
• the Vf will rise to probably 100 mV from 20 to 30 mA on Red HB. It will probably run fine at 30 but risk reduced MTBF Sep 29 '19 at 22:33
• Resistors limit current because they drop voltage across themselves (check on Ohms Law) thus leaving less voltage to produce current in the rest of the circuit. Sep 30 '19 at 0:01