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Well Trevor, you're not as bold as I am (birthday in profile) but your secret is now out.but in my day we used standard rectifying diodes such as the BY100.
Chris, you will need to pedal quite hard to catch me up.Well Trevor, you're not as bold as I am (birthday in profile) but your secret is now out.
Chris
Because it's not a MOSFET. It's a dual gate JFET. Unlike N Chanel MOSFETS JFETS conduct between the Source & Drain with no bias on the Gate. Their characteristics more closely resemble that of a Vacuum Tube than a MOSFET. R8 (as small as it might be) provides some negative bias between the Gate and Source.and the C4 will block the DC, how come the MOSFET be biased?
I looked up the BF982 and I found it is a MOSFET. It has protection diodes across the gates which will act as oscillation limiters and provide AGC action so no additional diode is necessary.Because it's not a MOSFET. It's a dual gate JFET. Unlike N Chanel MOSFETS JFETS conduct between the Source & Drain with no bias on the Gate. Their characteristics more closely resemble that of a Vacuum Tube than a MOSFET. R8 (as small as it might be) provides some negative bias between the Gate and Source.
Chris.
There are many types of oscillator, given different names. This one would be a classic Colpitts without C3. It has a whiff of Clapp about it.
The best exposition of oscillators that I have seen is "Electronic Designers' Handbook" by Landee, Davis and Albrecht.
Damn! As I typed that there was a little voice saying "Are you sure of this? Check this FET out before committing yourself ".I looked up the BF982 and I found it is a MOSFET. It has protection diodes across the gates which will act as oscillation limiters and provide AGC action so no additional diode is necessary.