Front and Back

Coefficient Potentiometers Rack



Special Functions Rack



Integrator Rack



Control Rack

Wire

Some photos of the special functions rack, which is now - after several mammoth wiring sessions - complete.

 

Knot Theory

Cannot resist messing about - now special functions rack nears completion - here I have put sin(x) on the horizontal axis of the scope, and Bessel function J₁(x) on vertical axis (here x(t) is a triangle wave)...yields a Lissajous-like figure...looks something like a figure eight knot...

5 V per division (XY-mode)

Front Panel Furniture

Orange banana jacks arrived from US and wiring of the front panel furniture for the special functions rack continues...with a bit of testing as I go along...

Final Rack

At long last, work is under way on the final rack (number four) - special functions ( I use the term somewhat loosely - trigonometric functions are here also). A slight hiatus whilst I await delivery of some orange banana jacks (from USA - we have nothing like that over here!). Front panel drilled and being populated...so far the thing looks like this:

Zero Limiters

The final board...essentially just a couple of ideal diodes / precision rectifiers:

There's also an analog switch (DG403) too (the pins of this are just taken to jacks on the front panel - for the user to make use of as he/she sees fit).

Limiter

Here's the limiter circuit (one of two separate channels is shown):

It's based on a circuit from 1959 [1]; the glass 6AL5s being replaced by the also glass 1N4148s:

Trimmer C1 is retained and proves useful in setting the left (or right) part of the transfer characteristic flat. 

[1] 'Function Generation With Operational Amplifiers', H. Koerner and G. A. Korn, Electronics, November 6, 1959, pp. 66-70.