railway RRB JE (CBT I + CBT II) Mock Test 2024 Electronic Devices Optical Devices Light Emitting Diode (LED)
What value of a series resistor is required to limit the current through an LED to 20 mA with a forward voltage drop of 2.0 V, when connected to a 10-V supply?
1
600 Ω
2
200 Ω
3
800 Ω
4
400 Ω