In Morgan Jones book (the chapter about Mu-followers), a brief description of a JFET (2SK147) acting as a ccs between 6J5GT triodes is described.
Anyone tried this topology and has any comments about it?
Anyone tried this topology and has any comments about it?
I have used Jfets as a part of a cascode circuit for constant current sources. Works just fine. I don't really think they are any better or worse than a depletion mode mosfet. In fact a depletion mode mosfets actually acts fairly similarly to a jfet.
Jones already talks about the tradeoffs doesn't he? In the 4th edition:
"In theory, we could replace the bipolar transistor and its associated components by a JFET. If the gate is connected directly to the source, a typical 2SK147 becomes a 9 mA constant current source. However, rd (the output resistance looking into the drain) is typically 10 kΩ, so it is not as effective at reducing distortion as the β-follower."
"In theory, we could replace the bipolar transistor and its associated components by a JFET. If the gate is connected directly to the source, a typical 2SK147 becomes a 9 mA constant current source. However, rd (the output resistance looking into the drain) is typically 10 kΩ, so it is not as effective at reducing distortion as the β-follower."
