[Elecraft] KPA500 Parts

Tue Aug 16 11:30:14 EDT 2022

The latest revision of the schematic for the KPA500 TR Switch shows a Zener
diode at the gate of Q4 in place of R3, the 100K resistor previously.  Its
obviously for gate protection.  There are no markings on the schematic what
this diode is although the spec sheet for the IRFSL9N60APBE does say the
gate-source threshold is maximum of 4V.  Anyone know what the value of this
thing is before I just stuff in a 4v Zener?

Dr. William J. Schmidt - K9HZ J68HZ