Random Voltage Source
A random voltage source is useful for creating “surprises” within a patch, even surprises to the patcher. Don Buchla is often credited with the idea, and his 165/265/266 “Source(s) of Uncertainty” and “Dual Random Voltage Generator” are generally the basis for descendent models like the Wiard Richter Wogglebug.
Units such as this will often have a noise source included and to some extent will act as a noise coupled with a sample-and-hold to generate random voltages at a triggered interval, but also there will be quantized random voltages to keep the output at semitone intervals. There is usually some kind of voltage control over the range of voltages (degree, here,) the number of stored voltages that can be output if quantized (states) and various controls over the probability of the occurrence of change in voltages or gate-levels.