4841 Diode and LED

What is a diode

Diodes is a electrical component that is use in circuits to only allow electric currents to go one way. 

P= P-type (hole)             A= Anode +
N= N-type (electrons)    K= Cathode -

How to pick a diode.
-Choose the correct amp needed
-Choose the correct voltage needed


Diodes are sold in amps and voltage
eg      1A                       3A
     1N4001   100v    1N5408
     1N4004   400v    1N........
     1N4007  1000v   1N.......


above are example of diode.1N4001 can handle up to 1A and 100v. 1N5408 can handle 3A and 100v. 1n4007 can handle 1A and 1000v and so on....




LED (Light Emitting Diode)

LED's are diodes that light up.They were first use as indicators but are now use in many devices eg TV, Cars, Cell Phones..... They come in many colours (even once that can change colours) , shapes and different sizes  8 mm, 5 mm and 3 mm.




Work out resistor to use with it
R=resistance
Vs= Voltage supply
Vl = LED Voltage (2V for all but 4V for white and blue LED)
I= LED Current needed (20mA change to A =0.02A for formula)


Fomula
R=(Vs-Vl)/I


eg R=(12V-2V)/0.02
      R=500ohm