500 Watt Inverter schematic diagram

How to Build a 12 VDC to 220 VAC Power Inverter (UPS)

How to Build a 12vDC to 220vAC Power Inverter (UPS) uninterruptible power supply


Power inverter is a device which converts 12 volts to 150 volts of D.C into 220 volt to 110 volt. Power inverter is commonly known as UPS. UPS stands for uninterruptible power supply which is the modified form of inverter. Due to the lack of electricity the importance of inverter increases day by day. The substitute of load shedding is generator or UPS.

Few advantages and disadvantages of generator are as follows.

Its first advantage is, it can run many electronic devices and it can supply electricity for the long duration of load shedding. The disadvantages are noise pollution, usage of fossil fuel cost it too high. The alternate of generator is UPS, it has also some advantages and disadvantages.

The supply of electricity goes uninterrupted, it do not require much effort. Its backup depends on battery, as many amperes of the battery it has, that much it backup it would provide.

Its disadvantages are, recharging takes a lot of time and in the long duration of load shedding battery cannot b recharged so that it stops working. By putting excessive load the duration of backup reduces. Its performance is about 60% to 90%.

Today I will teach u how to make 500 watt inverter which anybody who has fundamental knowledge of electronics can make it.

Following things are required for its construction.


  • Transformer 40 amps (500 W), 220 V, 12X12 V
  • Transistor (10) 1047
  • Resistor (1) 500 ohms
  • Battery 40 Ampere
  • Multi meter
  • Capacitor 250 V, 0.5 uf
  • Wires, soldering wires,
  • Soldering iron


First of all you have to make some changes in transformer. If you are using 500 V transformer then take 18 to 22 gauge copper wire and on the one side of transformer’s core make five turn and put a point on it, and turn this point, and again turn the wire five times on the same direction.

In this way you get three terminals. If you are connect the transformer to 220 V power supply then it gives 1.5 V on both terminals.

How to fine Base, Emitter and Collector:

Now put transistor D1047 on the palm of your hand and turn it such a way that number appears your way. Now you will see three points. The point on your left side is known as (B) Base, middle one is collector(C) and the right one is (E) emitter . (These are the information only for D1047)


500 Watt Inverter schematic diagram

500 Watt Inverter schematic diagram

500 watt UPS inverter circuit diagram

Now first of all tight the 5 transistor in heat sink in series with the help of nut bolt. Connect the base of all five transistors altogether and then join the points of collector together.

In the same way arrange the other five transistors individually and connect the collector(C) of both sides of transistors with the outer terminal of secondary coil, after that connect the both outer terminals of the third coil with the base of the both heat sinks of transistor. then connect the (E) emitter of both side by wires n then connect the 500 ohm resistor on emitter and resistor on either side. Now connect the middle terminal of primary coil by one to two ft long wire and clip (crocodile) it and attach this terminal always by the positive terminal, and with the negative terminal of battery connect the both (E) emitter of transistor.

After that the central point of the third coil and a wire attach it with emitter to connect using a heavy ampere switch between both terminals of the Inverter primary coil to apply a capacitor which will prevent the current from the sparking. inverter will switch on as soon as starting to work.

Discussions about Pakistan Science Club's Power Inverters 12 VDC to 220 VAC UPS, you can find problems, troubleshooting and construction help Please visit Power Inverters (UPS)12 VDC to 220"


With both the terminals of battery connect the positive and negative wires to its terminals positive to positive and negative to negative and then open the switch, slightly vibration starts in the inverter as switch is open. Now you can run it into 1 to 500 watt load.

Power Inverter Wattage Chart

inverters voltages (Input) Transformer Amps Transformer watt No of Transistors D1047
50 watt inverter 12 V 4 A 50 W 2
100 watt inverter 12 V 10 A 100 W 4 to 6
300 watt inverter 12 V 25 A 300 W 6 to 8
500 watt inverter 12 V 40 A 500 W 8 to 10
1000 watt inverter 24 V 45 A 1000 W 20 to 26
3000 watt inverter 24 V 125 A 3000 W 40 to 50
5000 watt inverter 48 V 105 A 5000 W 60 to 70
Note. table shows that requirement of D1047 transistors for different power inverter wattage


You will need to switch off for battery charging and connect the primary coil indirectly with 220 V of power supply, after that battery will start charging. To converts it into UPS you needs only one relay. These relays are AC 220 V and 4.4 terminals.

 inverter circuit diagram for battery charging

inverter circuit diagram for battery charging

For online help visit http://forum.paksc.org/Forum-Homemade-UPS-inverter

Trouble shooting:

If you do not start to switch on to check the following items

1. Spark the place where resister is attached for one second

2. If it will not start yet then detached the connection between base wire and coil and rearranged it.

If you want further details then join Pakistan science club All right reserved This project cannot be published without the permission of science club

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