View Single Post
Old 21st Mar 2017, 7:24 pm   #20
G6Tanuki
Dekatron
 
G6Tanuki's Avatar
 
Join Date: Apr 2012
Location: Wiltshire, UK.
Posts: 13,951
Default Re: Frequency counters

The "JFET Source-follower" does work - I've used it extensively. You need to take care to accept and acknowledge the wide variability in individual JFET pinch-off characteristics and adjust the bias accordingly.

[There's something to be said for lifting the earthy-end of the gate-to-ground resistor and feeding it from a potential-divider across the supply rails: then adjust this potential-divider to get approximately half the DC supply-voltage at the source]
G6Tanuki is offline