I am connecting digital output from a camera to a light source using a relay (see below).
The relay uses SONGLE SRD-5VDC-SL-C Optocoupler:
The camera manual says "Uses an open-drain NFET transistor with the source connected to GND in camera. If used with an external relay, a diode must be connected in parallel with the load for protection against voltage transients. Max loading is 100 mA."
It seems to me there would be little possibility of transient voltage. I am seeking advise if the TVS or Flywheel diode is really necessary?