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Compact PCB For All JFET Circlotron

Posted 25th January 2011 at 12:59 AM by Michael Rothacher
Updated 2nd October 2011 at 11:59 AM by Michael Rothacher

This is the artwork for the PCB in the pictures. It fits into the ExpressPCB miniboard profile so it's a little cheaper to have made.

It will be necessary to check the orientation of the bias pots (I can't remember). I wouldn't want you to blow-up your $30 JFETs.
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  1. Old Comment
    ichiban's Avatar
    I've been searching for the schematic of the JFET version with no luck. Could someone point me to it? Thanks in advance.
    Posted 5th February 2011 at 08:08 PM by ichiban ichiban is offline
    Updated 8th February 2011 at 07:20 PM by Michael Rothacher
  2. Old Comment
    Michael Rothacher's Avatar
    The entire article can be found at Pass DIY.

    There are no changes in the JFET version. Just drop 'em in.

    Only the bias adjustment is different, since the Power JFETs bias up around 2V.

    The same instructions apply.
    Posted 8th February 2011 at 07:18 PM by Michael Rothacher Michael Rothacher is offline
  3. Old Comment

    Current through the Output Stage


    Given 2V gate to source for the R100 jfet, does this still give you 1.2A through the output stage? If it doesn't, then what current are you getting?


    Posted 5th April 2011 at 12:37 AM by Ejam Ejam is offline
  4. Old Comment
    Michael Rothacher's Avatar
    I still adjust for around 1.2A through the output stage. The Vgs will depend on the particular sample and should fall into the 1-2V range.
    Posted 27th November 2011 at 01:22 PM by Michael Rothacher Michael Rothacher is offline
  5. Old Comment
    crt's Avatar

    resistor rating

    except 0R47 and 100R
    are 1/4 watt resistor enough?

    since i already have 47R/1watt and put it 2 in series to replace 100R, is that sufficient?

    i have R100A laying around and got interest to build all Jfet version
    which one do you prefer, mosfet or jfet?

    best regards
    Posted 2nd September 2015 at 10:32 AM by crt crt is offline

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