Found in American documentation from the 90's, this JFET stage has an input impedance of 500 M ohms. Bipolar transistors are general purpose types and the FET supports an equivalent.
In the figure we have the way to control a triac with a low current and low voltage switch,...
This trigger circuit was found in old European documentation, but it can be implemented with...
May 2017 - The new ROHM SFR series anti-sulfur resistors can now be obtained from Mouser...