The design presented on this page utilises a basic CMOS one-shot IC 4047 which is used here as a 50Hz oscillator. The power stage comprises of MOTOROLA npn power transistor type 2N3773. The need for pre-amplifier transistors is eliminated by using n-ch Power Mosfet type IRF540 supplied by many companies. Although this circuit is a little old fashioned according to modern standards, it provides a good insight on the working of power invertors. A demonstration project can be made out of this design by reducing the power transistor pairs and using a smaller transformer. The below described circuit has been fully tested by powering a desktop PC and the backup time has been found to be 2:15 hours using a 60Ah Lead-Acid accumalator. To avoid complexity, protection circuits are excluded. The design is only experimental and it SHOULD NOT be used commercially to power sophisticated electronic devices.
Some general features of this circuit are..