Peter,

The device you mention can be substitued for the FQP8P10 I use in the
Basic Pulser. This device itself is a substitute for the IRF9Z34 as a
near equivalent.

You can use any of the 95** or 96** series devices as the MOSFET. If
use with a correct balance of inductors you will likely have a more
powerful desulphator. My 'High Power' devices use a IRF9630 at the
moment.

Changing any one component will result in such as the value of R2
needing to be altered to prevent excessive heat build-up in either
the MOSFET or the inductors. Similarly if you change any of the
inductors.

I'm not sure about a site for finding equivalents other than
comparing devices directly.

Regards

Richard