Silicon Diodes
A standard diode is normally used in robotic applications to limit the flow of current in one direction. It's purposes are for circuit protection from Back EMF. When a coil or motor has power removed from it, the magnetic field collapses causing a reverse current to flow in the circuit. Under normal operation the diode will be turned off not allowing flow of current, but when the reverse current from the Back EMF flows through (reverse direction of the normal flow of current), the diode turns on allowing the current to flow back into the coil protecting the circuit.
Diodes are commonly made from silicon which have an approximate barrier voltage of .7V. This is the minimum voltage before the diode (turns on) allows for current to flow through. In a circuit that the diode is in and turned on, the voltage drop across the Silicon diode will be approximately .7V.
If the current is in a reverse direction the diode will not turn on up to a limit. This limit is known as Reverse Breakdown Voltage limit. When the voltage exceeds these limits, the barrier can no longer hold back the current and breaks down causing the current to flow through possibly causing damage to the circuit. You must keep this in mind when deciding which diode to use.
| References: | Diodes Incorporated |
| Wikipedia - Diode |
