Änderungen
Aus Hackerspace Ffm
/* Circuit */
[[Datei:Raspi_USV.png|UPS circuit for Raspberry using Supercapacitors]]
The powersupply goes in at the left side, the diodes prevent that current will be flowing back to the power supply and the resistors R5/R6 limit the current at startup rushing into the Supercaps (otherwise the diodes or the power supply might die). The diodes should be schottky-diodes with a high current and low V_foreward rating, so many types will do. SR430 SR340 was choosen only because it has been found in the drawer. R5/R6 could also anything between 0.5R and 2R but high wattage types should be choosen - especially at startup they might get hot.
The supercaps C1/C2 must be connected in series and the resistors R1/R2 are used that the voltage over the caps will be distributed evenly (balancing), otherwise the caps may degrade quickly. The resistors also discharge the caps slowly when the circuit is not powered (but within a quite long time) that is also good to lenghten the live of the supercaps.
