Four Quadrant Divider

Misappropriating Mr Plato...A circuit which can properly divide is to be considered a god...

After messing about with AD633s I opted for the AD734 (allows an external denominator voltage/direct denominator control). The transfer function is (X₁ - X₂)(Y₁ - Y₂)/(U₁ - U₂). Much more interesting than multiplication because of the can of worms which potential zero divides opens up. All the difficult stuff is done by the AD734, but the things has proliferated to no fewer than eleven chips...some switching to handle a negative denominator (if U₁ - U₂ is negative it is swapped and the output inverted), plus various checks e.g. that the magnitude of X₁ - X₂ is less than 1.25 that of U₁ - U₂ (required by the AD734).

I had to buy a bigger breadboard(!)...

The final construction...

Mounted Hardwear

I've made the front panel for the control rack. I used FrontDesigner 3.0 to do the artwork. Simple to use program - recommended. Printed the artwork out on to matte photographic paper. Two A4 sheets are needed to cover the 19 inch panel (but join is pretty much invisible). Covered the image side of the paper with a double sided acrylic adhesive film. This was then used to stick the photographic paper to the back of a piece of 0.75 mm polycarbonate sheet. Holes drilled out with a small bit thence hand reamer. Easily enough (apart from the bigger holes which, in hindsight, are best dealt with using a round file - not a big blacksmith's drill).

A bit of a long winded process, but not expensive (except in terms of my time!) - and gives a pretty durable/hard wearing front panel. By the way, the background colour is vanilla cream (#FCFBE3) and the text slate blue (#004080), font is Verdana.

|x|, x^2 and xy

Two independent absolute value circuits...input is x, output is |x|, and - for good measure - x squared (divided by ten). Plus three independent basic multiplier circuits...input is x and y and output is xy/10.

Next bit of circuitry is a divider. Then I need to build four summers and some reference voltage stuff and odds and ends, to complete the integrators rack.

In other news, front panel for control rack has been drilled and awaiting completion of artwork.