The ADSRjr is an envelope generator with many features. Standard gate input jack is normalled to the Doepfer bus gate signal. Three time ranges cover times from tiny to huge. Linear or expo curves are jumper selectable. A cycle button creates continuous waves.
The expansion module brings out a metric boatload of features: CV control of each segment, trigger button and jack, buttons replace the linear/expo jumpers, end of attach, decay and release outputs, and an inverted output.