Confetti502 Analog Junction

That's an analog controlled junction board for the analog computer Confetti. It's functionality is basically like a vactrol, one can use the board as an voltage controlled resistor.

When using it in an analog neural network the Confetti502 Analog Junction board should be connected to the triangle output of a Confetti501 Confetti Neuron. That allows one to control for example the cross modulation of some neural oscillators.
But for the input any other voltage source could be used, too.

The board behaves at the output like a variable resistor in the range from 95 Ohm to 370 KOhms. An other resistor or a diode could be plugged in the socket. That will be now in series to the one on the board. If no resistor is needed a wire should be plugged in the sockets.

For the design two H11F1 optocoupler are used to control two output resistors. One has to trim the two potentiometer for the ideal control of the output resistor range. The two measure points Vpp and Vmin are marked on the board. One potentiometer is for the attenuation, the voltage at Vpp should be peak to peak 6V. The second potentiometer adjust the voltage level. The minimum voltage should be 3V.
After trimming the potentiometers the signal at Vmin should be in between 3V and 9V.


Paper PCB