This Lamba Diode is interesting...

In a short, I think that I understand how it works... A robbing Vgs game, mostly...

Since the Jfets are tied together by their sources, and since they need opposite polarities Vgs, when any voltage builds, it turns a Jfet more (more Vgs), but doing so, at the very sametime, it turns the opposite polarity Jfet Vgs lower... There is a voltage where both Vgs are at an equilibrium point...

It looks very important that the Jfets are used in their "resistive" region. 

The curve "peak" is reached when |Vgs (N Jfet)| is exactly |Vgs (P Jfet)|...



The Jfet/Transistor combo works the same way... If the transistor is removed from the scheme, and the Jfet source connected to the gate, it is connected in a "constant current source" way... But putting the transistor back and moving the gate source to the collector pin is, when closing the loop, forcing the current flowing through the transistor emitter a constant value... The emitter to collector current is made a constant one.


The drain to base loop is forced 0.65..0.7V... (the version shown here...). But with Germanium transistors, should be interesting to experiment...

A strange cascade, if you ask me (LOL !!!)... But my favourite would be this Jfet/transistor combo... Far easier (IMHO) to "fine tune"..... But a drawback ... The supply voltage has to be ways higher (probably several volts...)...

JBL