Stromquellen - Schaltungsvarianten, Funktion, Konstantstromquelle vs. Konstantspannungsquelle

Are current and voltage sources the same? How can you keep the current constant? 0:00 - introduction 0:55 - Difference between current and voltage sources 3:00 - current sources with a bipolar transistor 5:50 - current source with 2 transistors 6:43 - current source with JFET 8:00 - current sources with OPV 9:14 - Constant current from voltage regulators