N4004 Rectifier Diode is an excellent device which stops electricity flow on positive wire in one direction. Let's say you have a set of LED lights with 2 power sources and you don't want one power source backfeeding into the other power source, then all you have to do is install 2 of these diodes on the positive leads of each power source. They will stop electricity flow from one power source into another. Diode's stripe is on the side which stops the flow.
power source 1 -> diode || (stripe on this side) -> led light <- (stripe on this side) || diode <- power source 2
Rectifier diodes are designed to stop electricity from flowing in the wrong direction. Diodes are sometimes known as rectifiers for their use to rectify alternating current electricity into direct current, by removing the negative portion of the current. When the diode is in forward bias, the diode allows current to flow from anode to cathode. In a reverse bias current is blocked so there is no flow of electricity through the circuit. When current is flowing through a diode, the voltage on the positive leg is higher than on the negative leg, this is called the diode's forward voltage drop.
N-type: With N-type doping, phosphorus or arsenic is added, in parts per billion, to the silicon in small quantities. Phosphorus and arsenic both have five outer electrons, so they are displaced when they get into the silicon lattice. The fifth electron has nothing to bond to, so it's free to move around. It takes only a very small quantity of the impurity to create enough free electrons to allow an electric current to flow through the silicon. Electrons have a negative charge, hence the name N-type.
