Warning: this may be an extremely naive question (if so, please enlighten me).
Many applications of relays require a flyback diode to protect against inductive voltage. I'm unable to find any relay that incorporates a flyback diode.
Since it's such a common need, why don't relays include a flyback diode inside the relay package? Are there just too many factors to consider, making it hard to guess the circuit's need?
Best Answer
There is simple answer to this question - there are many flyback schematics and the reverse diode is the simplest one. Although it has one big disadvantage - it makes the relay to switch off very slow.
This way, sometimes other schematics are to be used. There are several examples:
simulate this circuit – Schematic created using CircuitLab