Abstract: This device, by its organization and operation, processes sound, usually music. It provides output voltages, for driving lights, which is proportionally representative of input sound levels. Range of sound perception of the human ear exceeds the range of perception of the human eye. It is necessary to adjust the sound level by compression and Automatic Gain Control, particularly by compression, to accommodate the eyes. A requirement to have the output drive voltage drive the lights is to have a linear response to the compressed audio signal. This requirement is met with an output drive circuit which, has a linear response to the compressed signal. This is achieved with a linear firing circuit when providing output voltage using SCR's or Triacs. In a straightforward variation of the output circuit to improve the power factor, the linear response is maintained by modulating the output with transistors instead of using SCR's or Triacs.

Abstract: A system that varies the brilliance of light bulbs in accordance with modulated audio signals. The audio signals are first compressed and then passed through a comparator. The comparator has two inputs, one of which is the aforesaid compressed audio signals. The other input is a control input which receives a second voltage in the form of a series of impulses. The compressed audio signals pass through the comparator if and when their voltage is higher than that of said second voltage.

Abstract: A Hall effect probe having output voltage leads arranged across the surface of the probe so as to eliminate the distorting effect of voltages induced in the leads by a varying magnetic field includes in a three lead device, voltage leads connected at opposite corners of a rectangular probe and laid across the surface of the probe at an obtuse angle with respect to the edge so as to define a predetermined surface area. The leads are vertically stacked at an intersection point and extend parallel with one another and with the input current lead until clear of the magnetic field.