JFET-only Circlotrons without negative feedback

[Yurik_V]

Printed circuit boards for these gerberas were ordered twice and there were no complaints from the manufacturer. I fixed the gerberas and uploaded to the manufacturer's website.
Please note that some of the transistors on this board are Russian-made. The wiring of these transistors does not coincide with the generally accepted among world manufacturers. If necessary, I can fix the board for other transistors.

JFET-only Circlotrons without negative feedback. - Share Project - PCBWay

 

[jpatay]

If necessary, I can fix the board for other transistors.

Jura, it would be very nice to develop a PСB for 2SJ103, 2SK246, J112.

 

[UltimateX86]

Jura, it would be very nice to develop a PСB for 2SJ103, 2SK246, J112.

Hi,

yess please

So I could made it with lateral mosfet

 

[Yurik_V]

PCB without russian semiconductors.

Link for ordering PCB:
JFET-only Circlotrons without negative feedback v2 - Share Project - PCBWay

 

[jpatay]

PCB without russian semiconductors.

Link for ordering PCB:

Thank you!

 

[Sebastian K]

Yurik, is the pinout for the UJ3N power JFETs intended for bottom mounting? (TO247 package, pin order is G-D-S.)

Also, what is the recommended supply voltage range?

Keep up the good work guys, you have my full interest

 

[Yurik_V]

is the pinout for the UJ3N power JFETs intended for bottom mounting?

Yes, transistors on the bottom side of the PCB.

 

[jpatay]

Also, what is the recommended supply voltage range?

The supply voltage can still be increased, but it is important that the transistors of the differential stage withstand the maximum voltage.
The author of the scheme, Svjatoslav, is still working on increasing capacity.
Valuable suggestions for improving the scheme are welcome.

 

[jpatay]

Circlotron test on UJ3N065025K3S.
YouTube

 

[UltimateX86]

verdict, lateral or Jfet ?

He made some mease ?

 

[jpatay]

verdict, lateral or Jfet ?

He made some mease ?

Alexey Semin:'' JFET is more balanced, better damping. JFETs sound one to one, like a tube amplifier with triodes. Laterals sound like a pentode tube amplifier. So choose who you like.''

 

[UltimateX86]

If Jfet sound like 845

he managed to test Jfet and lateral on the same PCB just by adjusting the potentiometers ?

 

[jpatay]

ECW20N20-S are also good transistors.

 

[jpatay]

he managed to test Jfet and lateral on the same PCB just by adjusting the potentiometers ?

Yes. The current is adjusted by changing the negative stabilized voltage.

 

[nigelwright7557]

Wide question. It works very stably.
Even at low rest currents (50 mA) there is no "stair".

In addition, the small JFET transistors in this switching circuit turned out to be very resistant to breakdown voltage.
Which allows you to increase the supply voltage.

If you look up depletion mosfets on RS Components website you will see Microchip do some high voltage depletion mosfets.
I tried them in my new amp design in the LTP and they worked great.
Just be aware the pin out is mirrored.

 

[jpatay]

If you look up depletion mosfets on RS Components website you will see Microchip do some high voltage depletion mosfets.

Can you give a link to JFET?

 

[nigelwright7557]

Can you give a link to JFET?

Here is one of the type i used.

MOSFETs | MOSFET Transistors | RS Components

 

[jpatay]

Sorry, but we need JFET.

 

[nigelwright7557]

Sorry, but we need JFET.

Whats the difference ?

 

[Svjatoslav]

Whats the difference ?

Significant difference. No less than in the powerful variants. Because technology is the same.