precision power unit

9-08 — elektor september 1980 precision power unit As we all know it is virtually impossible to construct a precision voltage source with standard components. Close tolerance devices (both active and passive) are very difficult to obtain. If resistors are connected in series and parallel to produce the required value, a tolerance of 0.1% is out of the question. The solution, therefore, is to find integrated components with "everything included". The majority of so called precision voltage regulators suffer from the disadvantage that they can only provide one output voltage. Elektor"s The voltage across RSET is buffered by an opamp before being fed to the internal series pass transistor. The IC contains integrated 0.1% tolerance resistors between various pins which can be interconnected to provide a combi- nation of values. Resistors with values of 5 k, 10 k, 2 k and 6 k are located between pins 9 and 7, 7 and 6, 6 and 5 and 8 and 4 (ground) respectively. The output current is de...