Can you use a Vivitar 40d flash with nikon?

Can you use a Vivitar 40d flash with nikon?

If the Vivitar flash is old and the Nikon a newer DSLR, be careful as the trigger voltage of the Vivitar may exceed the safe voltage of modern DSLRs.

It might work, but then again, it might fry your camera's flash triggering mechanism.

The reason is that older cameras had a mechanical triggering mechanism that was generally voltage immune, while modern DSLRs have electronic triggers that are intended to be used with modern flash units designed for DSLRs as these have low-voltage triggering circuits.

Caution is in order. I would not attempt to use the flash unless I could find out what voltage it presents to the camera is, and whether or not that voltage is safe for the camera. On the other hand, if the flash is specifically designed for newer DSLRs, then you are probably OK.