Warning: DO NOT CONNECT DIODE or LED DIRECTLY TO THE POWER! This movement might burn your circuit and cause hazard!
A diode is defined as a two-terminal electronic component that only conducts current in one direction (so long as it is operated within a specified voltage level). A diode has two terminals or pins, anode and cathode. An ideal diode will have zero resistance in one direction (Anode to Cathode), which is said to be “forward biased”. And infinite resistance in the reverse direction (Cathode to Anode), which is said to “reverse biased”. The most common diode we use is light-emitting diode (LED), which is included in the kit.
Since the forward biased diode has negligible resistance, directly connecting the power with diode can cause high current and burn the circuit. The diode must always connect to a resistor serially to protect the circuit. The voltage drop measured across a forward-biased diode during conduction is known as forward voltage drop. Normally, a silicon diode has a forward voltage drop of 0.6V. When the voltage of the circuit is higher than the reverse breakdown voltage (normally above 50V), the diode is able to conduct electricity in the reverse direction (i.e., the “high resistance” direction). Reverse breakdown voltage can destroy the diode. This is why in practice we say diodes have a high resistance in the reverse direction – not an infinite resistance.
Diode voltage vs. current plot
Light-emitting diode
A light-emitting diode (LED) is a semiconductor light source that emits light when current flows through it. Electrons in the semiconductor recombine with electron holes, releasing energy in the form of photons (Energy packets). The color of the light (corresponding to the energy of the photons) is determined by the energy required for electrons to cross the band gap of the semiconductor. White light is obtained by using multiple semiconductors or a layer of light-emitting phosphor on the semiconductor device.
A single-color LED has two difference length legs. The long leg is anode and short leg is cathode. When you connect the LED to the circuit, make sure the anode is linked to the positive of power and cathode is linked to the negative of power. Make sure a LED is connected serially with a resistor. DO NOT CONNECT LED DIRECTLY TO THE POWER SOURCE!
LED diagram