Dilshan R Jayakody’s Web Log

This is a high voltage, low current, offline, AC adjustable power supply for electronic/electrical experiments. This power supply is mainly design for switch mode power supply (SMPS) experiments and to drive basic high voltage electrical circuits. Thanks to the isolated step-up transformer this power supply breaks the ground loop and provides shock free – safer high voltage output. This offline (or isolation) feature preventing accidental current from reaching ground through a person's body. This unit generates 50Hz or 60Hz (selectable at runtime) square wave AC output, and it is capable of generating output voltage between 150V – 290V AC (on no-load state). Prototype version of offline high voltage AC power supply As stated above this power supply unit is mainly design for SMPS experiments. This is not work well with liner power supplies because transformers in linear power supplies are get overheating from square wave inputs generated through this unit. This is a hig...

In this project we design an Inverter to convert 12V DC power source to 230V AC power. This system consist 3 main stages such as oscillator, switching circuit and step up transformer stage. In oscillator we use 4047 CMOS astable multivibrator to generate nearly 60Hz oscillation. In a given configuration, f = 1/(4.4C 2 (R 1 +R 2 )) f = 1/(4.4×(0.1/10 6 )((3.3+33)×10 3 ))) f = 62.609 Hz In a switching stage we use 2SD400 NPN transistors and IRFZ44 N-channel FETs. For the step-up transformer it is recommended to use 12V-0-12V : 230V – 5A transformer. When constructing the circuit it is highly advisable to apply good heat sinks to both Q1 and Q2. If you are plan to use single heat sink to both Q1 and Q2 it is required to place good insulator between the transistors and the heat sink. During the field test we use 12V - 7Ah sealed lead acid battery (which was commonly used in general UPS) with this system and constructed prototype deliver 238V AC in no-load. To get the c...